ROCKVILLE, MD (WUSA9) — A man has been charged with sexually assaulting a woman on a Red Line Metro train, WMATA said Monday.

A woman told police that she got on the train at Rockville. A man—later identified as Orin Gill, a 25-year-old from Silver Spring—sat next to her and started talking to her. While riding the train, the man forced her to engage in various sexual acts, she told police. It all happened between 10:30 p.m. and 11 p.m. on Saturday, March 31, Metro said.

The victim and Gill exited the train at Medical Center, where she contacted authorities about the alleged incident.

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The man got on a Red Line train heading in the opposite direction. Officers from Montgomery County and Metro Transit Police arrested him on an unrelated warrant charge at the Shady Grove station.

Metro Transit Police said they reviewed and preserved video evidence from several locations for the investigation.

Gill is still in custody on the other charge. He’s now also facing a count of second-degree rape.