He only saw a flash of leg, for an instant, as he entered the apartment building (tenement was more like it). The back of the knee, a bit of calf, a spiked heel - too shapely for this place, the shoe too expensive. Even if it wasn't suspicious, though, the momentum of that leg would have dragged him around the corner. Curious, impetuous, horny; whichever, it was, he bit.
He edged around the corner in the most nonchalant yet cautious way he could figure and saw an empty hallway flanked by a dozen grungy doors emblazoned with number plates that might once have been brass, but had long since given up and adopted the uniform dingy brown common to the bad side of town. No sound of a door closing - she either hadn't used one or was on to him and closed it quietly - no light from beneath any of the doors. Nothing. He was going to have to move from this spot, and figured a jaunt outside was better than being ambushed inside.
Past the mailboxes and out the front door to the drizzle and grey - every window shut tight, no sign of a skirt. Inside then - nobody in heels like that could shimmy out a window that quickly. Inside was the ticket, but when he turned to get back on the trail of his quarry, he saw that grim, flat face again, this time looking out the window instead of from above him as he lie flat on his back in the alley. Not wanting a repeat of that unfortunate scene, he turned on his heels and beat a hasty retreat to his car. Guns weren't an option here - it turn into Custer's last stand. Time to file this away for future use and pursue another loose string - the Chinese laundry.