NEW YORK (AP) – New York City police say they have arrested a repeat sex offender after undercover officers caught him assaulting a woman on a subway train.

Darrel Corian was arrested Tuesday on charges of persistent sexual abuse and forcible touching. Undercover officers say they noticed him pacing on a subway platform at Grand Central Station in Manhattan, and followed him onto a train. Police say officers caught him rubbing his exposed penis up against at 19-year-old woman’s backside, and arrested him.

Corian was paroled two weeks ago after serving time for persistent sexual abuse and was supposed to stay off buses and subways. There was no telephone listed at an address provided by police for Corian.