Typically forensic evidence refers to physical evidence such as fingerprints, DNA, blood spatter, gun shot residue, and ballistics. This physical evidence assists to establish what happened during an alleged criminal act. Some say science is an objective witness, with no reason to lie, no reason to distort the truth, and no biases. Forensic evidence is presented in court through two types of expert witnesses (1) those who gather the evidence and (2)those who interpret what the evidence mean in terms of related scientific principles. For example, criminalists collect blood smears from the crime scene. DNA experts then test the blood in the lab, against available samples provided by a suspect. Criminal lawyers then subpoena the DNA experts to court to establish if someone's genetic materials is or is not present at a crime scene. While pure science does not distort, expert witnesses infuse their subjective opinions into the trial. Their motives are clearly relevant as they are typically financially compensated by the side that calls him or her to the witness stand. Say the Prosecutor calls a government DNA expert at trial to explain that Defendant's DNA was located at scene -- thus establishing that he may be responsible for the crime. In response, the defense lawyers will call its own DNA experts to disagree with these results, or to question the testing methodology. The high-profile Spector trial has experts from the prosecution and the defense battling over how established scientific principles apply to their divergent opinions. Tagged as: drug crimes defense, faq, jury trial defense
Law Blog on June 27, 2007 at 12:08 a.m. wrote: In the Spector homicide case which is pending currently in Judge Fidler's court, in the Downtown Los Angeles Criminal Courts Building, forensic experts are battling about how to interpret relevant crime scene evidence: (1) is an intra-oral shooting more likely to be a suicide or homicide? (2) does back-spattered blood based in its size, density, and characteristics travel 3 feet or more if someone is shot in the mouth? (3) does gun-shot residue on the alleged victim means she is more likely to have fired the gun? All these are relevant scientific issues the jury must consider, in light of expert testimony, to determine whether or not Spector pulled the trigger and is guilty of second degree murder.