A man threatened to kill Michael Jackson and his fans, a letter released by the FBI (Federal Bureau of Investigation) has revealed.

Frank Paul Jones claimed to be entitled to half of the 'Thriller' singer's estate and when no one responded to his threats, he said he would target President George Bush Senior.

The letter said: 'I'll commit mass murder at a Michael Jackson concert if necessary, in an attempt to murder Michael, then you will have to deal with my situation in the public.'

A later letter stated: 'I decided that because nobody is taking me serious that I am going to Washington to threaten to kill the President of the United States.

"Michael Jackson I will personally attempt to kill, if he doesn't pay me my money."

Other documents released by the FBI reveal that a special agent was sent on a trip to the Philippines to discuss allegations of sex abuse by teenage boys concerning the singer, who died of acute Propofol intoxication in June.

FBI agents also investigated similar accusations made by a teenager in the UK, who claimed that Jackson said he was touching himself during a phone call.

Around half of the classified FBI document concerning Michael has been released, although details of his death have been withheld as they are part of an ongoing investigation.