Expert Witness

Career Objectives

Applying scientific techniques to police investigation to provide information that represents evidence before a court

Professional Profile

Expert professional in the application of science that provides the best tools in the processing of any kind of evidence to achieve highest accuracy in judgments of responsibility due to the importance of a criminal sanction.

He has knowledge on different specialties of *Criminal and Legal Science, Psychology, Communication and *Expert report techniques.

Specific tasks or activities carried out in the profession

He participates in interdisciplinary teams carrying out the orders of people in charge of the investigation, such as public prosecutors or private or public attorneys.

He takes part in the search, review, monitoring process and *protecting the crime scene.

He *gathers evidence, verifies traces and investigates fingerprints in the crime scene.

He interviews witnesses.

He carries out *expert analysis or tests to corroborate or rule out hypotheses and scientifically confirm the existence of the crime or event to be clarified.

Among the different types of analyses to perform is to find out if some bullets have been shot by a certain gun in particular, if the signature of a check is forged, alterations or forgery of bills of exchange, invoices, bank drafts, passports, identity cards, testaments, driver’s licenses, lottery tickets, handwritten or typewritten letters, casino tokens or tickets for football matches, paper currency (notes), etc.

And so many types of analysis; Sometimes, it is the analysis of a substance that needs to be identified, whether poison, an explosive or a drug, or the classical liquid found in front of a deceased person by murder or suicide, and it must be said what it contains or does not contain. There are basic techniques he must know but if it is anatomical absorption, then the expert in electron microscopy comes into action.

His objects of analysis are microscopic samples, the almost invisible traces to bring them to light and contribute to solve cases. For that, he works in the laboratory using high-tech instruments, such as:

The spectrometer; thanks to it, a simple scratch, barely visible to the human eye, stands out as if it were its own light and if a text has been crossed out, subjecting it to different types of light, the erasure disappears and the original text can be read clearly.

The comparison microscope, which allows observing two different objects simultaneously, for example, to compare a real document with a doubtful one or to look for similarities between two fingerprints.

The profile projector, where projectiles or cartridges are analyzed in search of signals that can measure less than the tenth part of a millimeter, but that will show conclusively, that two cartridges have been fired with the same gun, for example. All the information obtained is stored for future references, so that it is possible to reconstruct the criminal history of a newly arrived gun by seeing the files. Sometimes, the serial number of the weapon has been deleted, or the barrel or the firing pin is not original. These manipulations can be detected.

He presents his results in expert’s reports.

With this information, he helps demonstrate technically or scientifically what happened; if the event was accidental or intentional, who did it, how, when and where it happened and other questions related to the investigation.

He performs the presentation, justification and defense of the results of his expert reports both in oral trials and public or private entities.

Occupational Field

Civil, magistrate and labor courts

Customs Administration; provincial, national and municipal

Insurance Companies

Securities Companies

Security Forces

Legal firms

Private and State Companies

Lawyer’s offices, providing advice individuals need

Free exercise of the profession as Expert Witness, being able to be hired case by case, or providing advice or consultancies

Estimated time of College years

3 years

Main courses considered in the study plan

Basic Training Courses


Physics (2 semesters)


Computer Science

Professional Area

*Criminal Law

General Psychology

Offender Psychology


Research Methodology

*Forensic Photography

*Forensic Surveying

Forensic Chemistry (2 semesters)

*Forensic Biology (2 semesters)

*Dactyloscopy and Fingerprint Skills Laboratory

*Documentology and Documentology Skills Laboratory

*Graphology and Handwriting Skills

*Ballistics and Ballistic Skills Laboratory

*Traffic Collision Reconstruction and Accident Expertise Laboratory

*Criminal Identification Systems

*Computer Graphics






*Forensic Photography


*Graphology and Handwriting Skills

*Traffic Collision Reconstruction

Vocation, Skills and Interests required in the candidate for this career


Interest in public service

Sensibility for human rights

Strong interest in achieving justice

Motivation to decipher enigmas


Tendency towards observation and attention to details

Ability for an organized and methodical work

Spatial Location

Fine motor skills

Analysis capacity, how to distinguish, separate and various different aspects of a situation or fact


Sensibility and respect for the fundamental rights of people

Desires to defend those whose rights have been violated

Help build a fairer and balanced society

Or any specific dream or longing which feels involved or oriented towards this direction.

Candidate’s Personality

-Methodical, detail-oriented, patient, organized. With the character necessary to witness scenes resulting from criminal acts

Work Scope


Work in qualified laboratories

In contact with places and victims of criminal acts

Related Careers

Criminalistic Science, Legal Medicine, Forensic Anthropology, Forensic Dentistry, Police

Glossary of Terms

*Traffic Collision Reconstruction: Its task is the reconstruction of accidents and crimes to analyze causes of all types. He performs the study of the causes with scientific foundations, logic of ideas and technology to formulate hypotheses that serve as basis for a specific test proposition.

*Ballistics: It is a branch of Criminalistics responsible for the study of firearms, of the phenomena at the moment of firing, of the spent casings, of the projectiles fired, of their trajectory and the effect they produce.

*Criminalistics: Study of “how” the crime was committed and “who” committed it.

*Dactyloscopy: It is the set of techniques and procedures which purpose is the study of fingerprints.

He looks for latent prints at the crime scene.

He classifies and puts ten-prints (printing of ten fingers) into files.

He analyzes and compares footprints (toes) (applicable mainly in newborns.

Among others

*Documentology: It determines the existence of forgery and adulterations in coins and notes, stamps, treasury bonds, title deeds, bills of exchange, shares, covered bonds, private company bonds, personal identification documents.

The study of inks, writing implements and paper, used to compose manuscripts.

He enquires into the existence of erasures, scrapes, washings, amended or tested documents and cuts. He rebuilds what was previously written in case one of these operations exists.

He determines the age of a handwritten or typewritten scripts.

He determines if the signature of a check is false, the alterations or forgery of bills of exchange, receipts, bank drafts, passports, identity documents, testaments, driving licenses, lottery tickets, handwritten letters, etc.

He makes the restoration of burned or old writings rescuing their possible original invoice.

*Protecting the Crime Scene: It consists of the photographic and detailed record of the crime scene, from general with panoramic, general, particular views, and even the smallest detail.

*Forensic: Adjective applied to any activity performed before the courts of justice.

*Forensic Photography: Photography allows recording and know data that would be unperceived during the observation of people, places or objects with the naked eye.

It allows clearly examining the crime scene, the identification of objects and characteristics of the place in which the evidence was found.

It allows highlighting the holes produced by firearms, projectiles and cartridge shells. It makes possible the distinction between blood and other fluids. It underscores the difference between footprints, etc.

*Graphology and Handwriting Skills: It is the application of the latest techniques in the identification and verification of scripts.

He determines the authenticity or falseness of the script and graphology, mainly manuscripts, signatures and rubrics (contracts, checks, bills of exchange, testamentary trusts, missives, anonymous), but also typewritten documents and others (official, commercial and private printings, etc).

*Computer Graphics: It is an illustrative technique of the crime scene, through three-dimensional images created by the computer.

It provides the conditions and general characteristics of the event and the place where it happened, without the need for visiting the physical location.

It allows reconstructing of what happened in order to find possible contradictions and thus rule out hypotheses of what could have happened.

This technique can be used in the illustration of traffic accidents, homicides, etc.

*Gather evidence: It is the collection of physical evidence.

*Expertise: Technical, scientific or practical skill a person has about a science or art. *Expert: Related to *expertise.

*Forensic Surveying: Drawing of the immediate area with a permanent record of the objects, conditions and relationships of size and distance, located in it. It is usually done on paper to scale, addressing the cardinal orientation.

*Criminal Identification Systems: System to make digitalized verbal descriptions.