Philly deputy charged with sex assault on underling

A 42-year-old supervisor in the Philadelphia Sheriff's Office was charged with sexually assaulting a 43-year-old female deputy sheriff while working with him, police said Monday.

Stephen Postell, of the 3000 block of South 74th Street in Eastwick, was arrested Friday and charged with indecent exposure, indecent assault, and simple assault.

The female deputy, who worked as a subordinate for Postell, told Special Victims Unit investigators last October that while she was working on assignment with Postell in May, he parked the vehicle they were riding under a bridge in the area of 16th and Westmoreland Streets and indecently assaulted her, police said.

She told investigators that on another occasion he sexually assaulted her at their workplace, police said.