An old movie with a weird government agent

It was and old movie, a thriller, i think, i can remember one scene from it, a detective (i think he was a government agent) in a trenchcoat described actions of a victim of a carcrash in a very exact detail, up to the exact time, he was very manic about it, he had slick black hair and had this aura of classical conspiracy theorist. He also used the phrase: “thirteen – very unlucky number” commenting on one of victim’s actions. I, sadly, can’t remember anything else about it, i really want to rewatch that scene, but i can’t figure out the name.