Petraeus affair: Agent Shirtless, FBI man who sparked inquiry, is named Jill Kelley complained to FBI agent Frederick Humphries about threatening emails from Paula Broadwell, who had an affair with David Petraeus. The FBI agent who set in motion the investigation that brought down David Petraeus as CIA director, but was ordered to stay away from the case because of his alleged infatuation with a woman who prompted the inquiry, has been identified as a veteran terrorism investigator, Frederick W Humphries II. The New York Times revealed the agent's name and reported that his colleagues described him as having "conservative political views and a reputation for aggressiveness." Before his name was made public, Humphries had been dubbed Agent Shirtless after it was revealed that he once sent a topless picture of himself to Jill Kelley. Kelley's subsequent complaint to Humphries about harassing emails from Petraeus's mistress, Paula Broadwell, set in motion the investigation that forced the CIA director from office. Humphries, a former military intelligence officer in the US army, is himself under internal investigation. The FBI ordered him to stay away from the Petraeus case, which did not fall within his expertise, because of his close ties to Kelley. Last month Humphries revealed the Petraeus probe to members of Congress because he said he was concerned about a cover-up. But the move could be seen as political with the potential to embarrass the president ahead of last week's election. "Fred is a passionate kind of guy," a former colleague told the New York Times. He's kind of an obsessive type. If he locked his teeth on to something he'd be a bulldog. Lawrence Berger, general counsel for the Federal Law Enforcement Officers Association, spoke to Humphries and then told the New York Times that he sent a shirtless picture of himself to Kelley in jest and that it was not sexual. "That picture was sent years before Ms Kelley contacted him about this, and it was sent as part of a larger context of what I would call social relations in which the families would exchange numerous photos of each other," Berger said. Humphries has been involved in a number of terrorism investigations including one involving Abu Hamza al-Masri who was extradited from Britain to the US in October on charges of involvement with al-Qaida and planning to set up a terrorist training camp in Oregon. Three years ago Humphries was involved in the controversial prosecution of an Egyptian student, Youssef Megahed, on terrorism charges in Florida. Megahed was acquitted by a jury and an immigration judge threw out an attempt to deport him. Humphries told the court that Megahed had searched the internet for information on Qassam rockets in order to attack American military vehicles in the Middle East. In 1999 Humphries, who attended high school in Canada and is fluent in French, was working at the FBI office in Seattle was also reported to have identified an Algerian terrorist, Ahmed Ressam, posing as being from Montreal from his north African French accent. Ressam was convicted of planning to bomb Los Angeles airport.