Basics Concepts Regarding Fingerprint Evidence in Court
The fundamental basis upon which all rules of evidence must rest [if they are to rest upon reason] is their adaptation to the successful development of the truth.
Funk v. U.S., 290 U.S. 371, 54 S. Ct. 212 (1933)
Forensic specialists and fingerprint examiners collect and analyze physical evidence, specifically fingerprint evidence. A basic understanding of how physical evidence is defined and the rules that apply to evidence is necessary to effectively present this evidence in court. So, let’s first review the basic concepts of evidence and the rules that must be followed to ensure that the physical evidence, such as fingerprints are admissible in court.
What is Evidence?
Evidence is defined as testimony, writings, material objects, or other things presented to the five senses (namely - see, hear, smell, touch or taste) that are offered to prove the existence or nonexistence of a fact.
What is Physical Evidence?
Physical Evidence can be further defined as material objects that can establish that a crime occurred, identify the perpetrator, establish a relationship between the crime and the perpetrator, or clear the innocent.
What are the different types of Evidence?
Evidence can be direct, known as ‘Direct Evidence’ or indirect evidence, also known as ‘Circumstantial Evidence’.
Direct Evidence proves a fact directly without inference. A witness testifying to personal knowledge derived through one of the senses, something they saw, heard, smelled, felt, or tasted is direct evidence.
EXAMPLE: "I saw John climb in the window."
Circumstantial Evidence is indirect evidence. Physical evidence, such as fingerprints is an example of circumstantial evidence. Circumstantial evidence proves the principal fact indirectly through a medium of other facts.
EXAMPLE: John's fingerprints were found on the inside of the window ledge of the burglarized house, inferring John climbed in the window. (Inference is a deduction, which the jury makes from the facts provided)
Circumstantial evidence can be just as strong or stronger than direct evidence. One factor that can affect the strength would be the credibility of the testifying witness. For example, a poor eyewitness may have less credibility than a confident and knowledgeable forensic specialist presenting print evidence that establishes the presence of the suspect at the scene of a crime.
RULES OF EVIDENCE
Chain of Custody
Chain of custody is the combination of documented "links" between the moment a piece of evidence is seized and when it is offered into evidence at trial. This is done by properly marking or packaging physical evidence collected and accounting for it until presented at trial. Chain of custody is necessary to ensure the evidence presented in court is the same evidence you obtained at the crime scene and it is in the same or substantially the same condition as when it was seized.
The Exclusionary Rule
The exclusionary rule excludes all evidence the court considers to have been obtained in an illegal or unreasonable manner. For example: You entered a suspect's home without a search warrant and seized evidence and the court rules your search was unreasonable. The evidence you seized and all evidence or information resulting from that evidence would not be allowed in court. This extension to the subsequent evidence and information is sometimes called "fruits of the poison tree".
Probative value is the concept that evidence must be relevant and have a tendency to prove or disprove any disputed fact that is before the court. Prints found on an object that the suspect has legitimate access to would have little probative value. Whereas finding a burglar's fingerprint on a jewelry box inside a house that the burglar has never had legitimate access would have great probative value.
Fingerprint examiners work within the criminal justice system and need to understand and abide by the rules of evidence. Every stage of a criminal investigation, which includes the collection and analysis of fingerprints, must be properly and lawfully done to ensure that evidence will be admissible in court.
Continue reading ... Court Acceptance of Fingerprint Evidence