PITTSBURGH—Police have charged a former western Pennsylvania prosecutor with promoting prostitution after an undercover investigation.

Authorities arrested 64-year-old W. Christopher Conrad on Wednesday. They allege that he drove a prostitute to and from appointments, and the woman told police that Conrad is her attorney and was allegedly aware that she worked as a prostitute.

Defense attorney Patrick Thomassey says he doesn't think Conrad is involved in any kind of prostitution and that he was just friends with the woman.

Conrad is charged with promoting prostitution, criminal conspiracy, and using a cellphone to communicate with a female escort.

Conrad was an Allegheny County prosecutor until 1998 and then became a defense attorney. He's being held at the Allegheny County Jail under $5,000 bail.