Photo via Metro Transit Police.

Metro Transit Police has arrested a contract employee on sexual offense charges after engaging in a sexual act with a MetroAccess passenger with an intellectual disability.

Detectives arrested Derrick Lamont Bowen, a 44-year-old Southeast D.C. resident and Transdev employee, last night, according to a release from Metro. MetroAccess provides door-to-door rides for people with disabilities who cannot use bus or rail services.

The alleged incident occurred on Tuesday morning in Laurel, Md. Bowen was driving a MetroAccess van and stopped it in a church parking lot on Claxton Drive. According to Metro, a “witness observed the driver of the van move to the rear passenger compartment where he then engaged in a sexual act with an adult female passenger. “

The witness called 911, and Prince George’s County police came to the scene and alerted Metro police. The victim was transported to a local hospital. Metro says that a review of GPS data from the van confirms that it was located at the church parking lot during the 911 call.

Bowen has been charged with third degree sex offense, fourth degree sexual contact and second degree assault.

In a press conference today, Metro General Manager Paul Wiedefeld called the incident a “sickening situation, particularly for the family.” He added that Bowen was vetted, and that Metro expects workers to be “professionals all the time whether they are contractors or not.”

Transdev has not replied to a request for comment. Metro began contracting with Transdev in May 2013, according to Metro spokesperson Sherri Ly.

Metro has conducted a survey of sexual harassment on public transportation to inform its ongoing advertisement campaign on the issue, but did not include MetroAccess in its questions.