As Craig Ferguson outlined on The Late Late Show Tuesday night, the series had received a threatening letter Tuesday that included an unknown white substance. (Said Ferguson in his monologue: “It’s a very scary situation … My first concern, of course, was for my staff. And by staff, I mean penis.”) Now, the powder, which resembled anthrax, has been identified. A rep for The Late Late Show has confirmed with EW that the substance in the letter — which was sent from a European address — was actually corn starch. “The LAPD and FBI are currently investigating the situation,” CBS says in a statement.