Forensic evidence includes many different types of evidence that are collected during a criminal investigation and used in a court of law. Typically, forensic evidence is collected and analyzed through scientific method: fingerprint evidence, bite mark evidence, DNA evidence, hair and fiber analysis, blood tests, and so forth.
Ballistics is the forensic science dealing with firearms and firearm projectiles. Specifically, the field of ballistics is concerned with identifying specific marks a firearm makes on a bullet, the angle of trajectory which a bullet travels after being fired, and the damage a bullet causes when it strikes a surface.
Ballistic evidence is used to identify the type of weapon that was used in the commission of a crime and other details of the crime—for example, where the shooter was standing in relation to his or her target. It may also tell whether a weapon used in one crime has been used in the commission of another crime where identical ballistic evidence was discovered.
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How is Ballistic Evidence Used in Court?
Any bullets left at the scene of a crime are collected by investigators and analyzed by forensic ballistics experts. These analysts examine “rifling” in the spent bullet, which can help identify the firearm—or at least the type of firearm—used in the commission of the crime.
When a gun is manufactured, spiraling “lands and grooves” are created inside the barrel of the gun. These ridges and indentations are known as “rifling,” and as a bullet passes through the gun barrel, the rifling of the barrel leaves characteristic markings on the bullet. Ballistics experts often conduct comparative examinations of two bullets to determine if their rifling patterns match and if they came from the same gun.
This can be useful in prosecutions by identifying a suspect based on his or her possession of the firearm used to fire the bullets found at the crime scene.
Ballistic evidence—including gunshot residue, angle of trajectory, distance from the target, bullet entrance and exit marks, and damage—are often used to reconstruct the events that transpired in the commission of a crime. For example, a person who says a gun accidentally fired may be proven truthful or untruthful by forensic evidence that shows the trigger pressure of the weapon, the angle of the gun when fired, and the distance from which the gun was fired.
Is Forensic Evidence Reliable?
For many decades, ballistics has been held as an indisputable science in courtrooms across the United States. However, defense attorneys have been challenging the reliability of ballistics for nearly as long as judges have been accepting it as evidence in their courtrooms.
An article published in the American Bar Association’s Criminal Justice Magazine highlights important court cases that show an increased skepticism of the reliability of such evidence. The article cites two court cases (United States v. Hicks and United States v. Foster) which both ruled against challenges to forensic approaches primarily because courts had accepted such evidence “for many years” or “for decades.”
However, more recently, challenges have made more headway. In United States v. Green, the court ruled that the forensic expert could testify that casings in bullets were similar, but could not testify that the bullets came from a specific gun “to the exclusion of every other firearm in the world.” This assertion that ballistic evidence could not specifically and exclusively identify the exact weapon which fired a bullet has been upheld and reasserted in numerous court cases since.
In 2009, the National Academy of Sciences issued a report acknowledging the limitations of forensic ballistics, saying that there is too much variability among weapons to determine how many points must match in order to achieve a given level of confidence in a result, and that more studies are needed to solidify and this type of evidence in order to achieve reliability.
FAQs
When an examiner opines that a fired casing came from a particular firearm, they are accurate more than 99 percent of the time. And firearms identification evidence never stands alone in a criminal case.
Can ballistics be used in court? ›
How is Ballistic Evidence Used in Court? Any bullets left at the scene of a crime are collected by investigators and analyzed by forensic ballistics experts. These analysts examine “rifling” in the spent bullet, which can help identify the firearm—or at least the type of firearm—used in the commission of the crime.
What types of ballistic evidence can be used to help solve a crime? ›
Gunpowder residues can help identify the shooter, or the location where a firearm was used; Termination marks can help identify the location of the shooter and the trajectory of the projectile; Spent bullet cartridge cases can provide important details of the firearm used, as well as links to other crimes; and.
What is an example of ballistic evidence? ›
Forensic ballistics involves the examination of evidence from firearms that may have been used in a crime. When a bullet is fired from a gun, the gun leaves microscopic marks on the bullet and cartridge case. These marks are like ballistic fingerprints.
Is ballistic evidence sufficient to convict a suspect? ›
Ballistic evidence can help solve a homicide case, even if you never find the murder weapon. Evidence from the bullet casings found at a 2006 murder crime scene in boulder, Colo., were instrumental in convicting the killer.
Can ballistics be wrong? ›
He first gave his ballistics analysts “sensitivity tests,” in which they were asked to determine whether two bullets were fired by the same gun. The analysts reached the correct conclusion about 76 percent of the time—leaving a lot of room for reasonable doubt.
How long does it take to get a ballistics report? ›
The timeframe from the recovery of ballistic evidence (crime guns and cartridge cases) to the notification of a NIBIN lead to all affected investigators should ideally occur within 24 to 48 hours.
Is ballistic bullet proof? ›
A bulletproof vest, also known as a ballistic vest or a bullet-resistant vest, is an item of body armour that helps absorb the impact and reduce or stop penetration to the torso by firearm-fired projectiles and fragmentation from explosions.
How do police ballistics work? ›
Ballistic identification is based on the fact that all firearms leave unique markings on the cartridge cases they expel when fired, leaving behind a sort of fingerprint that allows law enforcement experts to link cartridge cases to the specific gun that fired them.
How does forensic ballistics evidence solve a case? ›
Using a forensic microscope, they examine the evidence, looking for engravings (unique scratches and marks) left on the bullet during the rifling stage when discharged from the gun. These distinct engravings can allow the firearm examiner to tie the bullet to the gun.
The National Integrated Ballistic Information Network (NIBIN) is the only national network that allows for the capture and comparison of ballistic evidence to aid in solving and preventing violent crimes involving firearms.
Are ballistics still used today? ›
In today's crime investigations, forensic ballistics has become synonymous with using technology to match recovered bullets and cartridge cases to the firearms from which they were discharged – ideally leading to the apprehension of criminals in as little time as possible.
Is ballistic evidence admissible in court? ›
In upholding the conviction, the Supreme Judicial Court ruled that an expert may give an opinion as to ballistic evidence, but that given the subjec- tive nature of such opinion testimony, an expert's conclusion must be limited to no more than “a reasonable degree of ballistic certainty.” Id.
How accurate is forensic ballistics? ›
The overall false-positive error rate was estimated as 0.656% and 0.933% for bullets and cartridge cases, respectively, while the rate of false negatives was estimated as 2.87% and 1.87% for bullets and cartridge cases, respectively. The majority of errors were made by a limited number of examiners.
What are the individual evidence in ballistics? ›
Individual evidence can often be found on bullets. Each gun barrel has unique machining marks as well as wear patterns that can cause scratches or striae on a bullet, a kind of “fingerprint” that looks much like a barcode (Figure 15.10).
What are the limitations of ballistics? ›
The biggest limitation would be the condition of the evidence. If the evidence (bullets and cartridge cases) is too damaged or mutilated to reveal sufficient individual characteristics, then no comparison can be made.
Is ballistics an exact science? ›
Ballistics is not an exact science rather it is applied physics or applied science, which is subject to changes and improvement depending upon the demands of the modern civilization.
How reliable are ballistic fingerprints? ›
Ballistic fingerprinting efficacy as a tool of forensics is a matter of some controversy. On the one hand, many lawenforcement officials insist that ballistic fingerprints are as useful as ordinary fingerprints in linking a round of ammunition to a specific gun.
What is accurate range in ballistics? ›
Accurate Range – The distance within which the shooter has control of his shots. 3. Back Curve - This is that portion of the bullets trajectory that drops below the critical zone beyond the. point blank range.
