A former FBI agent named John P. O'Neill was obsessed with Osama bin Laden and Al Qaeda and warned of the threat of an attack on US soil. He took a job at the World Trade Center in the summer of 2001 and died on September 11th.
In 1971, a small group calling themselves the Citizens' Commission to investigate the FBI broke into an FBI office in Philly, stole over 1000 documents, exposed the extreme surveillance program COINTELPRO, and then sent these documents to the press, leading to the FBI shutting it down.
The founder of the FBI (Charles Joseph Bonaparte), who had also served as Secretary of the Navy and US Attorney General was the great nephew of Emperor Napoleon Bonaparte.
A nurse named Eileen Luongo in Florida reported seeing the 9/11 hijackers in the hospital she worked at. She reported this to the FBI and was subsequently fired from her job.