St. Louis’ top prosecutor is accusing the police department of using an “obstructionist tactic” to prevent drug and alcohol testing of cops who were present during the Russian roulette death of their colleague, according to a new report. In a letter released Tuesday, Circuit Attorney Kimberly Gardner chronicled the difficulties she says her investigators faced in trying to obtain blood tests of Officer Nathaniel Hendren and his partner in the hours after Officer Katlyn Alix’s shooting death last Thursday.