According to Mattingly’s testimony, Walker was approximately 20 feet away when he fired his weapon and shot the officer in the leg. But photos of Mattingly’s wound depict a bruising pattern and coloration consistent with having been shot from close proximity, according to Patrick McLaughlin, who teaches forensic science at the John Jay College of Criminal Justice and served as a detective in the NYPD for 20 years.
“The easiest way to know for sure if he was shot from close up is through a gunshot residue test,” said McLaughlin, who spent most of his tenure at the NYPD in the Evidence Collection Team. The test detects gun powder residue, the presence of which indicates someone or something was shot from within three feet. McLaughlin described the test as standard procedure in cases like this.
But no gunshot residue test appears to have been performed on Mattingly’s wound or clothing immediately following the incident or at any time before the end of May, when the criminal case against Walker was dropped. A preliminary medical report on Mattingly’s wound, which was part of discovery in Walker’s criminal case, found no visible soot or residue on Mattingly’s pants and indicates he was shot from “distant range.”
McLaughlin, who reviewed the preliminary report, said he thought it was plausible the unusual bruising pattern was caused by Sgt. Mattingly’s wallet, which was in his front pocket, even if he wasn’t shot at close range, as the crime scene photos suggest. The bullet went through the wallet and his leg, puncturing his femoral artery.
McLaughlin also thinks it’s possible that what looks like gun powder residue is actually something else. But he added that “in a case like this where you have the chance to let science help support or refute something, I just don't understand why you wouldn't perform the test.”