The FBI investigations of Michael Jackson stemmed from two California police investigations into allegations of child molestation. The first one arose in 1993. The point was regarding possible federal violation against Jackson concerning transportation of a minor across state lines for immoral purposes (according to Mann Act). The FBI that time did not pursue the possible violations of the Mann Act and instead acted in a supportive role to police investigators. Charges also were not pursued and Jackson settled out of the court with his accusers.
The second case was connected with computer analysis provided by the FBI for a second investigation into allegations of child molestations by the singer, for which he was tried and acquitted.
The FBI’s files were brought into public after the Bureau received Freedom of Information Act requests to release them after Jackson’s death in June 2009.