All he did was plant a list of Mafia names to make it look like Jim was researching a big expose on the Mafia and this was the one thing they missed when they trashed the office (he made a point of getting Jim's fingerprints on it beforehand). It had nothing to do with his alibi per se but to provide a fake clue implicating the Mafia for wanting to take out Jim (who was never doing any research on the Mafia to begin with).
hi, thanks for reply. Yes... that makes sense. But now I have a new idea, if it is like this, then it would be quite easy just to ask Jim's wife if he was going to write about mafia. She probably would have known :)