Morning Rush Hour Masturbator

I ride the F train regularly. In the morning, there is a man who masturbates to unsuspecting women and girls. He takes advantage of the morning rush hour as well as the numerous nooks and stairwells of the East Broadway train station. I've been working up the courage to confront this guy for months and got to the point of staring him down which scares him away from me and I think the train station for a few days. This confirms my theory that his excitement is based on his victims being unaware of what he's doing. This morning on my way to work, I see him again. He approaches me (hand in his shorts) as I dig in my handbag for my iPhone. Finally I get it ready and snap his picture just as he's near me. Unfortunately he ducked behind a stairwell. By the time I get the second shot it's of his back as he calmly walked away. Submitted by Jenny