Advances in DNA Testing

Advances in DNA testing, particularly forensic genetic genealogy, have significantly impacted the solving of cold cases, offering a way to identify suspects and potentially exonerate individuals wrongly convicted. These advancements, combined with techniques like Forensic DNA Phenotype, are making it possible to analyze degraded or limited samples, leading to breakthroughs in cases that were previously unsolvable. The development and expansion of databases that contain DNA profiles at the local, State, and national levels have greatly enhanced law enforcement’s ability to solve cold cases with DNA. Convicted offender databases store hundreds of thousands of potential suspect DNA profiles, against which DNA profiles developed from crime scene evidence can be compared. https://www.ojp.gov/pdffiles1/nij/194197.pdf

Forensic Anthropology and Unsolved Murders

Forensic anthropologists can assess the age, sex, and unique features of a decedent and are invaluable in documenting trauma to the body and estimating how long a corpse has been decomposing. Forensic anthropologists work closely with individuals in law enforcement and medical science—and especially with specialists in ballistics, explosives, pathology, serology (the study of blood and bodily fluids), and toxicology and are often expert witnesses in murder trials.

Fingerprints, Hair Samples, and Other Evidence

Evidence can be divided into two categories:

• (Direct) Testimonial – statements or the spoken word from the victim(s) or witness(es).
• (Indirect) Physical – also referred to as real evidence, consists of tangible articles such as hairs, fibers, latent fingerprints, and biological material.

Evidence that shows or proves that an instance has occurred without the need for inference is direct evidence. For example, testimony from an individual who witnessed a specific event is considered direct evidence. (Note – a testimonial is a statement made under oath). Other information regarded as direct evidence includes audio recordings of someone confessing to a crime or video camera footage showing someone committing a crime. Both testimonial and physical evidence can also be considered direct evidence.

Indirect evidence does not necessarily prove anything in a case, although it may provide a basis for inference about a fact. This type of evidence may include circumstantial evidence, which implies a fact without providing concrete proof. However, the more circumstantial evidence there is, the better it is for a case. For example, if there are footprints found at the scene of a burglary, this may narrow the scope of suspects, but not by much. If, however, strands of hair or clothing fibers are collected in addition to the footprints, the pool of potential offenders can be further narrowed down. The previous examples are all forms of physical evidence.