When Detective Crosetti talks about the time he was shot he said one of the bullets went through his vest because it was Teflon, which is not how Teflon coated bullets work. Despite being falsely called "cop killers" Teflon bullets were actually developed by law enforcement to better penetrate hard surfaces like windshields and car doors; but the properties that allow these bullets to better penetrate hard surfaces actually make them less effective at penetrating body armor.