Scapa worked with the FBI (Anyone want to dispute that?) Scarpa was there, so was the FBI. Johnson was given fake media credentials, and had a woman with him who was allowed by both the FBI and police to escape (Anyone want to dispute that?)
A man with no killing experience was given press credentials, he got close to Columbo with his companion, then after shooting Columbo was shot dead, yet not a single FBI or Detective there saw who did it!! Yeah, sure. Columbo's own son even said it was not the Mafia before he passed away.