PITTSBURGH, Pa. – A man has been charged with stalking and harassing an FBI agent who had investigated him by posting a fake sex ad online that included the agent’s phone number and address.

The charge against 47-year-old Frederick Banks, of Pittsburgh, was unsealed this week. A federal magistrate on Tuesday ordered Banks jailed until trial.

The agent isn’t named in the indictment and is identified only by his initials, T.P.

The ad identifies the poster as a “married white boy” who is seeking a male sexual partner for himself and his wife, described as a “blonde gorgeous girl next door type.”

The ad resulted in the agent getting two phone calls in response, prosecutors said.

The agent worked in Pittsburgh and helped investigate Banks before he was sentenced to five years in prison for a 2003 case in which he sold bogus and pirated computer software online, authorities and court records said.

Banks was later convicted in a 2004 case of trying to buy coins and other valuables online with bad checks and sentenced to an additional five years and three months in prison. He was released from prison in 2013 but was sent back for 14 more months after he violated his probation by opening foreign exchange accounts using stolen identities, court records show.

Magistrate Judge Keith Pesto ordered Banks jailed given his recent criminal conduct “coupled with the very different character” of the ad on Craigslist.

Banks had falsely claimed the agent held his girlfriend at gunpoint to get her to implicate him in counterfeit software, authorities said, and apparently sought retribution by posting the Craigslist ad.

Banks’ attorney didn’t immediately return a call and an email seeking comment Wednesday.