Criminalistics. Concept, object, method and purpose

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* Terminology

* Definition. Origin of the term

* Ethics

* Thanatology

* Identification of some instruments involved in a crime

* Fingerprinting

* Study the person by their tracks

* Ballistics

* Graphology


The enormous technological progress experienced by our century has led, on the one hand, the birth of new sciences and on the other, the development of science whose origins date back no more than the last century. In the latter case is criminalistics, whose concept under study, so methodical and try to clarify in this paper.



Unfortunately it is very strong, even today, is the confusion of the terms “Criminality” “Criminology” “CSU” “Police Technology” “policiologia etc., Which have different meanings despite concern disciplines that are closely related to each other.

The confusion occurs most often between criminalistics and criminology, most likely due to lack of information or misinformation. Much blame for this lies with the translators, who translate “Criminology” by “Criminality”, perhaps in part because the real dictionary of the Spanish Academy Criminalistica word there.

It is therefore very important to demarcate more clearly the boundaries between the sciences that most are confusing, starting Criminology.

But before I give you, as an advance, a rough idea of what criminalistics, to have a point of comparison.


Criminalistics is basically to determine how a crime was committed or who committed it. This idea is not complete, as we shall see when entering more thoroughly the issue, but for now will be useful to establish the desired comparison. Likewise, we should clarify that we use the term “crime” only for purposes of easier understanding, then you should really talk about “alleged criminal act” as we will see later.

Once outlined the idea of what criminalistics, turn to a brief review of the concepts of Criminology and Science Policy, or Policiologica Technical Police, to support our claim that these disciplines should not be confused with each other, despite the close ties that bind.

Notion of criminology.

Criminology is the discipline that deals with the study of the criminal phenomenon, in order to understand their causes and manifestations. In virtue, as stated, this is primarily because science-explanatory.

DIFFERENCE BETWEEN criminology and criminalistics.

Once you stated above, it is easy to grasp the difference between criminalistics and criminology: the first is primarily concerned with the “how” and “who” of the crime, while the second delves more into his study and raises the question of “why” of the crime.

Notion of politics technical or POLICIOLOGIA.

The other discipline that is often confused with criminalistics is Policiologia or Technical Police, forensic misnamed. Indeed, in this case not so much a science as an art or art as more than abstract principles and general rules consists of practices aimed at proper performance of the functions of the police, such as the persecution and apprehension.


We need to reflect deeply to capture the huge difference between this discipline and criminalistics, because while this is dedicated to scientific research eminently to determine how and by whom a crime was committed, police Policiologia technical or establishes rules only practices to the chase and apprehension of offenders.

Affinities between technical policy and criminalistics.

While it is true that the differences in these two disciplines are very noticeable, so is that certain affinities between them or close relationships. Indeed, as we shall instead mediate or final order of criminalistics is perched auxiliary organs administering justice, among other things, so that they can provide to the capture of criminals and the laying of corresponding punitive measures. Now, it is precisely the Judicial Police, in his capacity as auxiliary organ persecutory (Ministerio Publico) and the court (Criminal Courts), which through the application of the rules established by the Technical Police Policiologia or carry handles out the persecution and arrest of offenders.

We could say, then, that criminalistics and Technical Police are responsible for two different phases of the same transaction: the investigation, which has a) a first stage or phase may be called “determinative” in which it is establish or determine whether or not they have committed a crime, as committed and who committed it, the phase that handles the Criminalistica b) a second stage or phase may be called “executive”, in which, based on the specific data provided by forensic experts, is to apprehend the offender, corresponding to this phase Policiologia or Technical Police.

Once outlined the notion of criminalistics and set their differences with the disciplines that are confusing, we will, of vague and general notion that we established for comparison to the actual definition of the discipline at hand.



Hanns Gross, young Coroner, realizing the lack of technical knowledge that prevailed in most of the judges, a prerequisite to effectively perform the role of instructors, decided to write a book that contains all systematized scientific knowledge technical and applied at the time the criminal investigation in this work came to light for the first time in 1894 and in 1900 the editorial Pravia Lazarus in Mexico translated into Spanish by Max Arredondo, under the title of “Manual of the Judge” was Gross in this work who first used the term of “Criminalistics.”


The most common definition among most authors is that Criminalistica conceived as “auxiliary discipline of criminal law that deals with the discovery and scientific verification of the offense and the offender.”

Besides some other questionable points, consider that this definition suffers from inaccuracy in its last part, when talking about crime and criminal.

Indeed in criminology, to intervene in the investigation of a particular fact can not know in advance whether it is a crime or not, that is why we speak of “alleged criminal acts” as we shall soon to expose our definition.

We define criminology as follows:

Criminalistics is the discipline that applies mainly the knowledge, methods and techniques of natural science research in examining significant sensitive material related to an alleged criminal act, in order to determine, in aid of the organs of justice, and its existence either rebuild or identify and involve the activities of one or more subjects in it.

Explanation of the definition

DISCIPLINE: We understand discipline any branch of human knowledge. But one might ask if criminalistics branch of human knowledge, is a science or art, answering affirmatively in both directions. Indeed, criminalistics is a true science, in that it consists of a set of real or probable knowledge.

Obtained methodically and systematically organized with regard to a particular sphere of objects, in this case involving alleged criminal acts. Moreover, it is also a technique for solving specific cases, the expert in criminology applies the general principles or laws of the discipline. So once criminology is a theoretical science wing and an applied science or art.



Deontology is the study of behavior and professional ethics.

The Constitution is the supreme law governing two aspects: The Rights of Man and of the state organization. They were appointed in Mexico, “individual rights”.

One of the civic duty of every citizen is to understand the Constitution, to demand their rights and fulfill their obligations, that is, with the basic rules of coexistence.

Judicial magistrates are often faced with problems whose solution requires special knowledge, beyond their legal training, and in such cases resort to appropriate skilled in the art to which call for a review to clarify the point.

This collaboration built on practice and legal texts is what is called a “judicial expertise” the expert is one who performs it.

The expert function requires three functions:

* Technical preparation.

* Morality and

* Discretion.

No expert can be good if some of these conditions. The duty of an expert witness is telling the truth, but this requires: first know find the truth, and then want to say it,. The first is a scientific problem and the second is a moral problem.

In its investigation the expert must be methodical, thorough, clear and precise; aware of his technical and scientific capacity to study the facts objectively.

The expert will “opinion” in writing about research, using language censillo, but the expert must observe two things: The grammatical correctness and dignity of style, two formal aspects of scientific seriousness.



Thanatology: study all issues related to death and cooling processes, rigor mortis, lividity and presenting the corpse putrefaction.

The putrefaction: that is a chemical process putrid fermentation of bacterial origin on organic matter via enzymes that act on lipids, proteins and carbohydrates, causing deep changes in the body nauseating products leading to progressive destruction.

The result of this protein breakdown is aromatic body formation as indole and skatole, inorganic gaseous products: hydrogen sulfide, ammonia and carbonic acid.

Besides amines are formed: cadaverine, puyrecina and aliphatic diamines are products of the decomposition of albuminoid substances.

After the destruction of the corpse putrefaction is continued by incectos called WORKERS OF DEATH OR cadaveric fauna.

Macroscopic morphology


Identification of some instruments involved

In a crime

Identifying common tools is mainly cases of burglaries. The technique is to identify and highlight the microscopic characteristics of each weapon, is a resource of the most useful aid that have been added to the police or criminologita science.

The microscopic method which normally rests on the surface of the tool presents very thin lines can not be seen at first glance, because they are thin.

In direct comparison of the tool and its brand, trace stripes are naturally enhanced, while the tool are hollow, that is, the trace or mark represents the mirror image or opposite of the tool.

The test is an object as large as are the tools is difficult under the microscope, so that the observation is not directly but through a mold of the same material as a clay, powdered aluminum and wax to form a metal layer shiny or soft lead.

All traces of tools identifications, the angle at which the tool was sustained when it formed the brand plays a very important role.

If a knife is held at right angles to the object being cut, the distance between the tracks of the scuff marks will be better than when the knife is held at an angle. The appearance of the tracks also differ when using the knife who is left-handed.



Fingerprinting fingerprinting, is the discipline that studies the fingerprints, in this you can see two broad types. The latent and visible. The first are the most difficult to find, as it requires special equipment and chemicals to make them visible to the human eye, in the latter are those that are easy to see and can be detected with the naked eye. It should be noted that for both lifting requires personal skill and special equipment.


Study the person by their tracks

Criminal Investigation


It is somewhat ambitious determine the life of a person by their tracks but for the keen observer Was this monograph is devoted to studying the Crime and expertise of any kind since for a big spirit nothing is small. –


Study determination traces stature:


Subject 1: 33 CMS. DIF. Between cue and tip = (h) 1.78 cm.

Subject 2: 29.75 cm. DIF. ent. T and p. = (H) 1.75

Subject 3: 23.25 cm. DIF. Ent. And p = T (h) 1.71

And therefore determined that theoretically proper conclusion: the stride distance multiplied by 6.28 gives approximately proportional stature who left its mark through the tread except in cases of mild foot deformities and rough terrain. –

Some people make strides when walking but taking into account the length of a large footprint footprints rarely belongs to someone of short stature.

The origin of the traces is linked to genetic patterns and therefore discarded Western races to find oriental prints and vice versa (obviously in cases exact).

The depth of the footprints denotes the weight of those who walked, but regardless of the terrain, which can be ground (easier to identify), we know that if the cue tip is the most depressed is a person who walks upright and postage military, instead of being little and mostly visible cue tip someone talk about hasty footsteps and possibly mature.

Taken into account aspects such as:

* Length of foot

* Distance between tracks

* Depth of footprint

* Possible traces of dirt, clay or other ..

* And distance between tip and pad

It’s probably already get a brief overview of the subject in question, height, weight, origin, speed at which walked or ran, age (older people often shuffling and make small steps) and if the person is right, lefty, etc. renga.

Determination by measurement of the trace:

In this case is more difficult, according to my statistics the proportion that I made with a margin of error of 2 + / -3 ctmts. A measure of footwear multiplied by 613 giving us proportional height.

In criminal expertise is hard to tell because there are more people leaving a shoe print deformations, plus size wearers who wear sneakers with uneven ground because its air chamber and are rubber tip and increase the actual size footwear.

Example: Footprint of 0.30 CTMS. My value multiplied by 613 = 1.83 cm. Height. –

The speed

If the person is shown running through the tip deeper and lower in the heel, in addition to the major strides in a common step.

When running the strength and depth of the tread is 3 times higher.

Take into account that the strides are bigger but not disproportionate, the normal running speed of a person between 20 and 30 years is 200 mts. In 40 seconds, in my case is 200 mts. In 20 seconds.

Gender determination by the footprint

The first thing I learned in my boxing with prof. Laudonio Cacho was to coordinate the steps essential to determine future movements, one false step is dangerous, as the case of sex determination by the footprint, not to judge but soled shoes have triangular tip or deeper in the block, what is important is the layout of the tracks, women often mostly as walking in a straight line alternating left and right, the most significant fact is that the woman does not leave a big footprint printed rather than his foot for his shoes, because the women footwear is usually appropriate to your foot and has no tendency to bend the foot toward the center and warp footprint.

In the case of man is easier to determine their mark, by its larger size in the big toe and its most comprehensive form of support than women, male foot treads with greater indifference and tends to leave its mark throughout either with or without shoes.

Possible Age by the footprint

In childhood the prints are small and need not determine a particular aspect except in cases of dwarfism in which pathology is difficult to distinguish this condition a man with a child.

In adolescence they tend to open passages in V-shaped sign is as comprehensive footprint and follows their height, weight, and speed with these data should be a pre-diagnosis of the tracks to determine provenance and footwear, (usually sports).

In adulthood the steps tend to be more straight and is easier to identify with the data mentioned above.

In the footsteps of old age are at ground level and closer together, the track seems to be smooth-soled but because the elderly walk almost dragging his feet, his steps are safe and cling to earth ground with ease leaving samples following footprints in mud, aged women tend almost the same only difference in their shoes and speed.


If the depth of the tread left varies slightly over 4 tracks are obviously in the presence of a left-handed, for the untrained eye to notice is difficult to detect, however if the left is marked trail is a lame person.

If the prints are of similar depth is probably a righty.

Any disorder of the layout of the tracks especially to show different angles to possibly disoriented person under the influence of alcohol or drugs.

Origin of the person

When I refer to a term provenance is double, both to where that comes as branch genetics is its provenance.

When looking at traces of calcareous clay is presumably a person who comes from a more unstable place.

As if we find traces of sand in marshy soils, would clearly an indication that the person is from a sandy place, not necessarily the coast.

I can not elaborate more on this point as there are thousands of variants to identify data such as cigarette ash, tiny fragments of rock sediments and other factors.

But while we can deduce that a mark on Sarmiento Street bears traces of clay and shoe footprint is the origin of the person is of a nearby tennis club, something so obvious that it can be confusing as all the obvious .

Regarding the genetic origin of the person and his estate should be noted that the feet of people vary according to their nationality, in a brief explanatory this is the statistical factor:

Across Pie: Zones Slovenian Arabic and German.

Foot short and small: Areas of China, Japan and Korea.

Short thin Pie: India and periphery areas.

Big foot long: Areas of Africa.

Small but slim Pie: Areas of southern Italy and Greece.

This is only a statistical factor extra detail to corroborate previous data as height and weight (the weight depends on the terrain for which I have no space to explain).

The genetic origin is an accessory for research and is the most difficult to substantiate.

There are cases in which the perpetrators were tried by his surname rather than by concrete evidence.


Footwear is the easiest to determine in a footprint and we can classify them into three types:

– Sports-fem. and masc

* Formal (shoe) – fem. and masc.

* From hard work

* Military

* From the category I call” tourist” (hojotas, sandals …)

* The sports shoes usually tends to have a rubber surface that allows the athlete greater performance and which is easy to identify because its heel is great for the air chamber and its sole in almost all cases, their tip is thin and slightly curved inward.

In the criminal this footwear is generally worn by young thieves, requiring agile this footwear for climbing, jumping and running, the offenses are minor and are street robberies (punguistas), vandalism, and theft in pre-meditated and tall houses that climb by roofs and roofs.

The formal footwear, shoe, it is less easy to identify because its range is enough and we have to consider is its outline, square toe, pointed, rounded heel and a slight difference in the block with more depth, there are few completely smooth soled shoes, the shoe itself is more recognizable to the naked eye by the depth difference between heel and toe that any other details.

For women the female shoe has a taco longer and is much easier to determine.

The hard working footwear, as I would rate is one that is used in agriculture and trades as boaters.

Generally sandals or similar, almost straight and leave a trail so smooth characteristic footprint (the sole is made of wood) beyond its sole principal detail to determine if regular footwear hard work is to determine its geographic origin by traces of marine sediments, arable land, or whether humus, obviously refers to a person of active trade and wear.

Military footwear, is referred to boots, gaiters and the like, the boot is easily determined by their size and depth of the tread also features as a sole factor hard and tough in their outlines what makes us recognize.

The military boot is one that is almost smooth sole shoe form but with pointing, usually used in cases of military rank.

” The Tourist” shoes as I called it is the easiest to identify, for three fundamental aspects, a completely flat sole, a last which corresponds almost exactly to the foot and a rounded contour, it is customary to recognize these footprints in the footsteps the beach, flip flops or sandals whether the difference is minimal.

In the criminal expertise to guide the sandals are ordinary criminals such as drug dealers as herbs and is associated with their culture.

Personality by their tracks

This is the most ambitious part of the essay, explain a possible personality of the person as their tracks, while not anything remotely accurate is the subject of observation and deduction, aided by master of psychology Kremtcher separated three types of tracks with their equivalents in bio-types (physical and psychological classifications).

Footprint 1: Equivalent to biotype pcnico

Footprint 2: Equivalent to biotype Athletic

Footprint 3: Equivalent to biotype leptosomic

The mark 1 is easily identifiable is deep denotes something of obesity and short foot, corresponds to the type pcnico: These guys have a strong development of the visceral cavities, abdomen prominent, tendency to obesity, round head, wide and heavy , short limbs. These characteristics are defined at 40 years, have a face full and fat accumulation in the waist, buttocks and abdomen in women appear these characteristics at age 25.

Cyclothymic (TN). – Are subject cheerful, social, communicative, entrepreneurial, funny, make friends easily, they like the holidays are the center of social gatherings. They are extroverts, but change from one extreme to the other (happiness, sadness). They are divided into:

Hypomanic: In constant motion, joy.

Syntonic: Realistic, practical, humorists.

Phlegmatic: Quiet, quiet, sad. In this group we have: Mirabeau, Luther, Gall, Pasteur, Rembrandt, Goya, Beethoven.

Cycloid (TA). – When we cyclothymic worsens the cycloid. Present trends of crime and there are two phases: joys and depressions, are easily desanimables. To combat this trend drinkers and may fall into dipsomania. When we entered the picture worsen manic-depressive.

Manic-depressive (FP). – Mental Enfermad characterized by periods of manic phase, followed by states of deep depression that can lead to suicide

The trace 2 corresponds to the athletic type and it is observed, a precise footprint, medium or long standing, safe passage and firm enters into this category most of the steps, this is their constitution: We found a great bone and muscle development, chest and large head.

Viscous (TN). – Are enterprising, persevering, tenacious, preferring to work outdoors, play sports strong.

Epileptoid (TA). – Are subject explosives, their reactions are disproportionate to stimuli received.

Epilepsy (FP). – It is characterized by seizures. Its symptoms involve brain damage.

The mark 3 corresponds to the type leptosomatic is that thin shallow tread shaky and unsure, denoted stature and low weight, this is their constitution: Subject bodily characteristics are: long body, thin, small head, pointed nose, little fat, elongated neck. The exaggeration of type is called “asthenic”.

Esquizotmico (TN). – Are subject introverts tend to prefer meditation and isolation rather than participate in the group. They like reading, music, writing poetry, prefer serious conversation and tend to self-analysis. They are divided into:

Hiperestsicos: nervous, irritable, idealistic.

Intermediate: Cold, energetic, systematic, serene.

Anesthetics: apathetic, isolated, indolent, extravagant.

May be included in this group to people like Kant, Calvin, Robespierre, Descartes, Copernicus, Newton, Bolivar, etc.

Schizoid (TA). – When the subject is aggravated esquizotmico have to Schizoid.

Schizophrenia (FP). – A forms the basis schizoid schizophrenia, although not in all cases. This is a mental illness with symptoms of delusions, hallucinations and destruction of personality.

Taking bibliography of Dr. Fabian Mensias Pavon is determined contributions to the Crime and legal field.

1. Leptosomatic tends to crime planned, may be a hired murderer, is unemotional and no scruples.

These would be criminals early from settled propensity criminosa remarkable emotional coldness, persevering and calculating, with a predominance of the intellectual sphere on the other, the scam is perhaps his favorite crime. They are difficult to treat and easy to relapse.

2. Pcnico, has a tendency to commit crimes for mismanagement of funds, because of their tendency festive. They represent a small number in the crime, are of lower recidivism and greater adaptability.

Offenders would be late, great affection, given its cyclothymia, their inclination is subject to criminal maniacal or depressive stage where you are. In step maniacal, are common offenses against personal integrity, the offenses to the authorities and public order offenses. In the depressive phase, often called extended suicide, that is, the elimination of their loved ones and then suicide impulse of despair.

3. Athletic commits violent crimes advantage of its strength is channeled defectively. These guys have the highest recidivism. They are subject explosives and sometimes cynical. Are common crimes against life, physical integrity, theft and in general those violent execution.

In terms of risk, the first place is occupied by leptosomticos, while the latter corresponds to pyknic.

He criticizes his obsession Kretchsmer abnormality, to the point of having erected in order, however, even though in truth involves some degree review, their typology surpassed morphological typology, highlighting the psychic process.

A few final tips:

When observed traces should consider the following:

The climate and terrain

Using fingers themselves as reference pictures

Using loupe or magnifying lenses

Using tape

Good lighting

A pussycat research on the geology of place and should be in ceramic floor should be noted traces of soil and any dust or residue.

Mark the area of the tracks and keep out curious.

And finally good luck and follow your hunches.



Is called the polygraph lie detector, is a completely scientific instrument has been evolving in a very interesting way in the last 10 years. We currently have polygraphs mechanical, electronic and computerized.

In polygraphs find that are formed by three main parts, the neumografo, the galvanometer and the cardiograph.

The first is the study of breathing where breathing frequency reading, have few breaths per minute, the quality, the suppression, the second is studying the electricity of the skin, ie, the energy that We as human beings can have ups and downs and the third is studying the heart rate in a comprehensive, beats, heart disease, high and low pressure.

Mechanical polygraphs, are called also analogs, where the parts are completely neumografo and cardiograph and operated by pneumatic air or ventilation and electric galvanometer is part together with the graph runs through a small motor, where the readings achieved through liquid ink pens.

The polygraph mail, has a great improvement over the previous one, as it adds to neumografo and sensitivity cardiograph a button that helps to improve the graphical impression, especially in the second as the cuff is put less pressure and the button you can get a graphic large and clear, the impression of the graphics are done with tinnta continuous liquid on paper, the operation is simple and improves its information.

The computerized polygraph has entirely revolutionized the previous two models, as through a program has three functions, the results can be archived on a floppy or hard disk in the same computer, this can help to reprint all of the charts necessary to perform manual studies, however the polygraph has built a program where it produces a result of chance lie.



The ballistics studies the movement and behavior of projectiles.

FOR study is divided into:

Interior Ballistics: Study projectile motion inside the canyon.

Exterior ballistics: Study the displacement of the projectile during its trajectory in space.

Ballistics effects: Match action and consequences caused by projectiles when hit.

Forensic Ballistics: It is a specialized branch of criminology to investigate the behavior of simple or complex test bullets and traces related to the use of firearms.

Its purpose is established by means of a technical process, correlation and origin of the intrinsic evidence with firearms as they are, caps and bullets that are collected during a criminal investigation.

Comparative Ballistics: Applies to the physical treatment of the signs. Is the search, detection and comparison of special features that identify the weapon with respect to the specific brand bushings which are printed during the process known as firing actions.

One of the indications that may provide important information is the cap consisting of a cylindrical tube, generally of brass, closed at its ends in order to hold the load and accommodate projection on the front end portion of the projectile body consists of mouth pellet or base and cap.

Are studied in the gall traces left by collision parts ejection gun and also the roughness characteristics of the plunger needle.

Extractor marks can determine the position of the sleeve prior to firing, which are in front of the rear edge of the sleeve, and with the oblique light against the shiny highlights and oxidized bottom cap smoked.


Writing is a graphic record of automatic gestures ordered by the central nervous system and automatically conditioned, physiological and psychological imposed on the personal character and permanent graphics.

Their study is used to recognize an individual whose identity is unknown when the writer distorts or modifies his writing to make it unrecognizable. Writing disguised contains individual characteristics, constant own involuntary made to the layout that allows the identification of the writer.


To identify if a document has been written by the same person or has been altered by another individual, we have methods of identification:

a) – Grafoscopio. Modern writing.

Use the data provided by the study of the general characteristics of writing by comparing literal forms and finding individual peculiarities.

b) – Grafometria. Measurement of writing.

The method is to measure the texts, enlarged by photography, series of sizes of the same order and represented by curves; relationships and variations lowercase heights, height of what stands; gladiolaje, separation of traits; relations angular values; parallelism grammarian, frequency and position of 10 points, and so on.


Gaby Villalobos