By Aubrey Whelan
In his back pocket was an envelope with a feverish, rambling letter inside, and two words scrawled on front.
It was Friday night, and down the street at the Maximum Level Lounge, the door was open and the drinks were flowing. A few blocks away, a young woman and her boyfriend pulled up to her apartment. Philadelphia Police Sgt. Sylvia Young, a 19-year veteran of the force, parked her squad car at the corner of 52nd and Sansom. Her shift was almost over. READ MORE OF THIS STORY