This unnamed man was a cop who became a Jefferson Starship.
He was one of a handful of humans transformed into a Jefferson Starship by Eve.
When Sam Winchester, Castiel, and Bobby Singer come to investigate a bar that erupted into a fight and left numerous corpses, this Starship along with two others arrested the trio and dragged them back to the police station. He personally put handcuffs on Bobby Singer.
While walking through the police station, with this Starship now accompanying Sam, Sam noticed the cops' reflections in a mirror and realized they weren't actual cops, but monsters. He headbutted this Starship and kicked him in the face, while Castiel and Dean decapitated the other two.
Before Dean arrived to the scene during the fight, but Sam advised he spare this Starship for interrogation. He was then taken to a room where Bobby tried to get Eve's location out of him, but he refused to answer. Castiel offered, despite his lack of mojo, to extract the information out of the Starship.
It is unknown what Castiel did exactly, but the Starship was heard screaming in agony moments before Castiel exited the room with Eve's location. When the Winchesters returned from bringing Joe and Ryan Silver to their uncle, his headless, bloody body could be seen still sitting in the interrogation room chair.