A veteran New Orleans police officer was arrested and placed on emergency suspension Monday after authorities said he hid evidence in an aggravated-assault case involving a suspect accused of killing another cop. Officer Wardell Johnson and his partner made the initial arrest of Travis Boys, who is accused of fatally shooting Officer Daryle Holloway while escaping from the back of a squad car just hours later. Police said Johnson deliberately attempted to leave a .40 caliber casing at the scene of Boys’ arrest and also neglected to process a recovered box of unused bullets. Johnson was charged with obstruction of justice, malfeasance in office, and theft, according to police. After police interviewed him, Johnson was seen throwing bullets he claimed to have misplaced out of his car window.