Ed Sheeran was the bait in a successful plot to swindle a charity out of 4 primo tickets to Super Bowl 51 ... according to cops trying to track down the scammer.
Marc Pollick -- CEO of The Giving Back Fund -- tells TMZ his charity got a call from someone promising to deliver Ed's singing services for a charity concert on the eve of the big game in Houston. Organizers and cops believe the con artist went so far as to forge Ed's signature on a contract.
The deal was Ed would perform 2 songs, and in return he'd get 4 suite tickets to SB51 .