Nathan Clinkscale, a D.C. police officer, is charged with third-degree sex offense in an incident involving a minor. (Courtesy of Prince George's County Police)

A D.C. police officer was arrested and charged with third-degree sex offense in an incident involving a minor, according to law enforcement officials.

The mother of a teenage girl called police after discovering Nathan Clinkscale, 25, of Upper Marlboro, Md., in her daughter’s bedroom about 1:30 a.m. Monday, according to Prince George’s County police.

Clinkscale engaged in a sexual act with the teen after the two met on a dating website, police said.

The officer was in the custody of the Prince George’s County Department of Corrections as of Monday afternoon.

Clinkscale is an officer in the 5th District, in Northeast Washington, and has been with the D.C. police for a year, according to a department statement. The department immediately put him on administrative leave upon learning of his arrest. He was off duty at the time of the alleged incident, police said.

“The allegations against him are disgraceful, and do not represent the standards of ethics our sworn officers are committed to upholding every day,” the District’s police department said in a statement.

An attorney for Clinkscale was not listed in online court records.

Peter Hermann contributed to this report.