Forensics is the use of scientific evidence in arguing a case in the court.  During the course of a case investigation, police will gather various elements of forensics to provide evidence for the case.  These elements may include DNA analysis, examples of handwriting, blood splatter analysis, pathology, and ballistics.  Any one of these pieces of evidence can be used by either set of lawyers to make a case for the guilt or innocence of the person of interest.


All of this evidence is collected at the crime scene.  This on-scene investigation is also known as a crime scene investigation. Unlike how it may be portrayed in the television shows and movies, the crime scene is thoroughly combed for evidence, the evidence is carefully and meticulously collected and marked, and all the information is sewn together using witness statements, expert reports, police reports, and photographs in order to formulate the most accurate explanation of what happened at the crime scene. In addition, it can take months or more to reconstruct a crime scene and perform a thorough investigation.  Therefore, anytime there is crime scene investigation, you need lawyers on your side that can help interpret results of forensics collected and reports associated with them.


A criminal investigation is a serious proceeding.  Depending on the alleged crime, a person accused of a crime can be faced with anywhere from months to a lifetime in prison.  Since each case has its own unique circumstances, you should only consider lawyers who have experiencing arguing criminal cases.  These lawyers will know the ins and outs of the criminal justice system, including how it works, what potential term each crime may carry, and how to present cases in courts to attain the best outcome that the law will allow their client.



Finger Print Analysis


Along with DNA, fingerprints are a main identifier for who we are.  We give them when applying for some jobs, they give access to our criminal records, and they can be used to identify who we are in death.  Even more importantly, when it comes to crime, fingerprints can help identify individuals who may have been at the crime scene.

Fingerprints can be found on almost anything that a criminal may have touched at a crime scene.  This can include doorknobs, pens, mugs, glass panes, and many other surfaces. In order to identify and analyze fingerprints, the crime scene investigators and forensic scientists will use a specific and specialized process.


Collecting the Prints


The fingerprints are collected using photography of dusting.  When a set of fingerprints is found on a smooth, non-porous surface, they will be dusted to make them visible, then photographed in high resolution.  To capture the fingerprints, investigators will place a piece of tape over them and pull it off, and the tape will subsequently be placed on a special card to protect it.  Images that cannot be dusted will have a photo taken with a measuring device next to them using a high-resolution camera.  Dyes and other chemicals, as well as other analyst methods can be used to identify these prints.




Law enforcement analyzes fingerprints in a crime laboratory.  The examiner will look at the collected prints under a microscope and match them against prints in a database.  To do this, they can use small parts of a print or a variety of print captures.  The analysis may also uncover physical features such as recurves, deltas, creases and scars that can indicate where to begin the comparison. The analyst compares minutiae characteristics and locations to determine if they match. Known prints are often collected from persons of interest, victims, others present at the scene or through a search of one or more fingerprint databases such as the FBI’s Integrated Automated Fingerprint Identification System.  The evaluation of prints will go through more than one examiner to verify accuracy.


Fingerprint analysis can take time if the prints are found to be conclusive. This process is quite painstaking for examiners, as they must identify every detail possible to match the print, find the person the match belongs to, find out if they are of interest, and have the prints verified.  However, this helps fine-tune the process of finding out what happened and who was involved at a crime scene into a more effective endeavor.

Forensic DNA Analysis


Even though people share some of the same DNA sequences, each person’s DNA is uniquely individual, just like their fingerprints.  Therefore, law enforcement can use DNA from a crime scene to identify who was at there and find out what may have happened from that person.  Certainly, the process for collecting and analyzing DNA is a detailed and long one.




The ideal way to collect DNA is by swabbing someone’s cheek, as this process includes the least contamination.  Sometimes this is not always possible because a court order is needed, but a court order is not always obtainable.  In this case, the investigators will use anything that may have the persons DNA on it, including blood, semen, hair, or saliva.  The DNA sample may be collected from a crime scene or from the person’s personal effects such as a toothbrush.




As described by the New Jersey National Institute of Justice, the steps for DNA analysis are as follows.


“Several basic steps are performed during DNA testing regardless of the type of test being done. The general procedure includes: 1) the isolation of the DNA from an evidence sample containing DNA of unknown origin, and generally at a later time, the isolation of DNA from a sample (e.g., blood) from a known individual; 2) the processing of the DNA so that test results may be obtained; 3) the determination of the DNA test results (or types), from specific regions of the DNA; and 4) the comparison and interpretation of the test results from the unknown and known samples to determine whether the known individual is not the source of the DNA or is included as a possible source of the DNA.”


By isolating the sample collected, processing it, determining what test to use, and comparing and interpreting the data, law enforcement can confidently pinpoint who was at a crime scene and use this knowledge for investigative reasons to solve the case or argue it in court.  This is a powerful tool in crime scene investigation and the litigation that surrounds criminal cases.

Handwriting Exemplars


Handwriting Exemplars are forensic evidence that can be used to help with a criminal investigation by analyzing the writing on a document.  Each person’s handwriting is a unique marker of whom they are, and it can even go as far as to project certain personality traits.  Using handwriting samples, investigators can show if a document matches another document from a person in question, or can help identify a profile for the person in question.  This can all be used in solving the crime and litigating it.


There are two types of handwriting exemplars that may be used; request writings and collected writings. Request writings are obtained from an individual specifically for the purposes of conducting a handwriting comparison whereas collected writings are samples the individual produced for some other, unrelated reason generally in the course of their day-to-day activities.  A handwriting examiner will look at the exemplar in question provide an adequate picture of the writer’s habits such that a meaningful comparison can be conducted with the questioned material.  This comparison can be used to place a person at the scene of the crime or help argue their involvement in the case in court.


When it comes to collecting handwriting exemplars, investigators will want it to be as accurate as possible.  This means that they will collect a sample as close to the date or the incident as possible that mimics the circumstances of the incident. These details will provide the investigator with an accurate picture of what the person in question was thinking and what was going on, as a person’s handwriting can change based on the situation.  The fresher the sample, the better the accuracy.


Canceled checks, contracts, applications, and business letters make suitable exemplars or standards. The writing can be properly identified, the date can be verified, and the habits of the writer can be studied. Additional standards may be needed if the words on the disputed writing do not match the exemplars.  When examining samples, the expert will look to match the same document types against each other.  For example, a check against a check would be a good comparison because it may require the same writing.  The examiner will then match letter vs. letter to see if there are striking similarities or differences.  For example, they will look at every “A” on each document, and so on.  They may also use special high-resolution equipment to analyze the writing to ensure it is accurate.


Exemplars are known handwriting samples used for comparison with questioned documents. There are two types of exemplars, formal and informal. Formal exemplars are request-writing samples. Informal exemplars consist of documents executed in the normal course of business and examiners will ensure that proper procedures are followed when taking request writing.


Blood Splatter Analysis


Blood splatter analysis is the examination of how blood was spread at a crime scene to help identify how the crime happened.  For, example, if blood is found splattered on a wall ten feet from the victim, investigators will use that as a marker for what caused the blood to splatter that far from the victim.  This type of analysis helps law enforcement, and later lawyers, tell the story of how the crime took place.


Blood stains range in distance and type.  From a pool of blood around the victim’s body to a patch of blood on the victims clothing, blood stains can construct two completely different stories.  In addition, the direction in which the blood splatters will help identify where the victim’s attacker may have struck from, which can lead to broader clues such as the location from where the attacker entered. All of these details help tell the story of the crime, thus aiding in prosecuting the involved and solving the case.


One example of how blood splatter analysis may occur is a gunshot.  Forward spatter from a gunshot wound will typically form smaller droplets spread over a wide area, while impact splatter – from a knife or blunt object, for example – will form larger drops and be more concentrated in the areas directly adjacent to the action.


Bloodstains can also be collected, usually done with high quality imagery or by cutting out the surface the blood is on.  A carpet or piece of square carpet are examples of how blood splatter is collected to be evaluated.  In addition, pictures of the splatter with rulers next to it will also be taken, as this is another way to evaluate the evidence away from the crime scene.

Blood splatter may also be soaked on a swab for DNA analysis, which is especially helpful when multiple victims are involved.  It can be a way to tell who was involved at what point as well as what happened to that person.  But first and foremost, blood splatter analysis is an identifier for who was at the scene.


When combined, all of these methods help investigators tell the story of what happened and how.  All of the blood splatter analysis can be combed through in a laboratory or in a separate location where examiners and experts can put the pieces of evidence together.  This evidence then provides a foundation for pressing charges and litigating the case.

Forensic Pathology


Forensic pathology focuses on identifying the cause of death by studying the corpse to give information to a crime investigators and the legal team.  When a death occurs at a crime scene, one of the big questions is “Why?”  The forensic pathologist answers this question by studying the corpse from head to toe to determine the cause of death.


Usually, a trained medical examiner will look for answers; to start, they will be trying to figure out the manner of death including a possible homicide, suicide, natural, or accidental death.  The autopsy will also allow for collection of evidence, which can be used in the investigation or trial; for example, a bullet fragment would be a prime piece of evidence for these purposes.  Also, the examination will include the documentation and identification of wounds and bruises.  This information will help investigators piece together what happened to the deceased, and it will lead them to investigate further based on what is found.  For example, if the death is ruled accidental, there may be no need for further investigation.  However, each case is different so the examination of the corpse is simply one part of a larger scope of work.


Forensic pathologists also examine the inside of the corpse.  For example, they may analyze tissue to see if chemicals such as asbestos of gunpowder are present.  Or, they may use it as a way of ruling out certain possibilities such as if certain drugs are not present like sleeping pills, they may rule out overdose or suicide. In addition, they will work with the fluids in the corpse to determine toxicology readings for substances like alcohol or opioids.


In addition to examining the body, the examiner may serve as an expert witness in court.  The combination of what the examiner finds along with their testimony can help with making certain arguments based on the findings in any given criminal case, which is why the forensic examiner plays such a vital role in criminal investigations.



Ballistics is the area of Forensic Science that deals with firearms. It provides information for how firearms are used, why they are used and why they are used frequently in the practice of murder. Ballistics is important for identifying the kind of weapon used in a crime and having this critical information can help investigators in their search for the perpetrator of the crime.  Thus, the field of ballistics plays an important function in the investigation of a crime, as well as later in court proceedings.


Examining the bullet, the nature of the wound, and any residue around the wound can help to determine what type of gun was used.  Because of the method that is used to make gunpowder, these markers can help determine if a gun was modified and how close the shooter may have been to the victim.  Plus, each gun has certain grooves in its barrel, and these can leave marks on the bullet as it is released.  This is one identifier that can help investigators determine the make and model of the gun used.  Furthermore, any shell casings left at the scene can identify the weapon used. All of these pieces of information together can help identify the gun used with a higher level of certainty than one measure alone.


The field of ballistics can play a large role in a criminal case.  It can connect the gun to the shooter, and it can express what gun was used.  Even more important is that the use of ballistics can be a way of tying multiple cases to one gun and one perpetrator, which can help solve cases involving serial murders or crimes done by the same person or persons.


Ballistics is an important forensic science. Through studying what weapon was used and in what manner, investigators can solve crimes faster.  Plus, the use of ballistics can be monumental as evidence for when the case is being prosecuted in court.


André Bélanger, a graduate of Loyola University, is a highly-respected criminal defense attorney serving the people of Baton Rouge, Louisiana, and surrounding areas of Ascension Parish and New Orleans, for one of Baton Rouge’s top-25 law firms. In his 18 years of practicing law, Mr. Bélanger has handled thousands of criminal cases at both the pre-trial and trial stage, including approximately 200 trials. This trial experience includes homicide defense and prosecution, large drug conspiracies and fraud cases making Bélanger one of the few attorneys capable of handling even the largest, most complex federal cases.