There are many ways to prove innocence or guilt. On TV, it often comes down to a dedicated detective and forensic science who uses fingerprints, bite marks or hair samples to make the case. The idea in these cases is that the evidence is unique to a lone individual. The process of elimination says only this person could have committed the crime.
While forensic science plays a role in real life criminal justice, it’s not the make or break evidence that it’s used for on TV. It can supplement an argument, but the data behind many plotline twists like bite marks and hair follicles doesn’t live up to its billing.
The scientific method
In the hard sciences, data goes through rigorous testing for universal, irrefutable proof. Fingerprints, bite marks, hair samples and other forensic staples have never actually been scrutinized to this degree. When an expert doctor or dentist gives their testimony, it’s based on their professional experience but not on universally accepted data.
Besides proper testing, a forensic scientist working with law enforcement is, in essence, part of the prosecution. In true science, the scientist is a neutral party. The connection between police and forensic scientists is a dubious relationship that may unintentionally influence conclusions.
Changes in testimony
The courts are making strides in how they use forensic evidence. The Department of Justice recently rolled out a new policy on language of testimony in court. For example, an expert cannot say they are 100 percent certain if fingerprints link a suspect to a criminal scene. There has never actually been a study to prove that all fingerprints are unique.
While these changes will help reduce wrongful conviction, it doesn’t remove misleading evidence from the courtroom. The new federal standards downplay how forensic evidence is presented, but it’s still a large factor in many cases. More importantly, the new standards only apply to federal courts, not state courts. Phrases such as “I’m 100 percent sure” are still allowed in Missouri courts, even when there is no hard scientific backing to prove it.
Evidence is the core issue in any criminal case. Its accuracy is paramount to ensure justice and to protect the freedom of innocent parties. Because criminal allegations can reshape your life, anyone facing criminal charges should consult with an experienced attorney to make sure that you explore every element of your case. Your freedom hangs in the balance. An “expert testimony” should require actual facts, not an educated guess.