Eh, he's old man sitting in prison probably spinning tales to anybody who will listen. He didn't tell them anything that wasn't publicly available, and on details that they needed to dig for into archives actually contradicts them ("Imagine that. Nobody’s ever seen him." about Rick, but he appeared before grand jury). Neither do they explain why such apparently notorious criminal would appear in the investigation only under alias in this case, but not in the many others mentioned (and why nobody that previously saw him as Rick noticed).

Yeah, was there no physical description of Rick Roberts? Did the other guys not know Thompson? If he was friends with Marcello it seems like he would be well known.