According to multiple sources close to the investigation, the FBI did investigate sexual assault claims by the man who is now accusing “X-Men” director Bryan Singer of sexually molesting him in 1998 … but he NEVER mentioned Singer. Michael Egan and his lawyer both said at a news conference Singer sexually abused him at a pool party in Encino, CA. when he was only 15. Egan also claims 3 other men abused him at the party. He sued the 3 men in 2000 but Singer was never named or mentioned. Our sources close to that investigation tell us … the FBI fully investigated Egan’s claims and the agency’s investigation was instrumental in criminal charges of sexual assault of one of the 3 men — Marc Collins-Rector — but Egan NEVER mentioned Singer and his name never came up during the probe.