Police and emergency responders in Millvale, PA were recorded on video laughing as they repeatedly stunned a handcuffed and mentally-ill man as he pounded his head against the side of a desk. The video -- surprise -- found its way to YouTube, and the police officers involved became targets of an FBI investigation, as well as a federal lawsuit.

Thomas Smith, 28, filed a $75,000 lawsuit against officer Nichole Murphy, Chief Derek Miller, and the Pittsburgh-area town of Millvale. The FBI's investigation is ongoing, reports WPXI, but no criminal charges have been filed to date since the incident late last year.

Smith was arrested on Sept. 21, 2012, and charged with public drunkenness. The video, shot on a cellphone, shows him without a shirt, and handcuffed on the floor of the police station, talking incoherently and pounding his head against the side of a desk.

Officer Murphy then uses a stun gun on him as paramedics or other officers laugh. Smith isn't seen attacking the officer, though she (Murphy) had reported in a police report, that she used the stun gun to subdue Smith when he became "violent."

According to the lawsuit, Murphy was fired before over conduct "similar" to what we see in the video, but subsequently rehired.

Mr. Smith pleaded guilty to disorderly conduct and public drunkenness.