The FBI unveiled hundreds of pages of its files on Michael Jackson today, including an investigation in 1992 of a man who threatened to kill the pop singer and then to do the same to then President George H.W. Bush, according to the documents.

The man - who according to the FBI falsely claimed to be the son of crime boss John Gotti - pleaded guilty and was sent to prison for two years. In a letter he threatened to commit mass murder at a Michael Jackson concert and to personally attempt to kill the singer if he didn't pay him his money, the documents state.

In another letter the suspect wrote: If they do not arrest me or solve my problem, I'm gonna attempt to kill President George Bush. 

The documents also details the many forms of assistance provided by the FBI to authorities in cases involving allegations that Jackson had abused children, the FBI said today.