BALTIMORE COUNTY, Md. (WJZ)–Baltimore County police arrest one of their own. The disturbing charges against the officer include sexting an underage girl and handcuffing a naked woman to a patrol car.

Gigi Barnett reports the officer is accused of doing this repeatedly.

According to charging documents, detectives were able to link sexually explicit cell phone message back to someone on the force.

While he should have been responding to emergency calls, Baltimore County Police tell WJZ that Officer Aaron Pross was having sexual relations in his patrol car while on duty.

Scathing charging documents reveal the five-year veteran was sexting a 16-year-old girl.

“He has let down his fellow officers and he has let down this agency,” said Cpl. Cathy Batton, Baltimore County Police spokeswoman.

Detectives were tipped off back in January when the teen’s father called them. He’d discovered the sexually explicit messages and videos on his daughter’s phone.

According to charging documents, the man on tape was masturbating while wearing bluish gray pants and a dark blue shirt, consistent with the Baltimore County police uniform.

A three-month investigation led police to Pross.

In the charging documents obtained by WJZ, detectives found nearly 150 sexually-graphic pictures and videos on Pross’ phone, including images of a woman performing oral sex on him in front of a marked Baltimore County police car. The woman was not his wife.

Detectives used the time stamp on the images to show that Pross took them when he should have been out taking police calls, including emergencies.

“We were able to determine that the sexual activity was occurring on duty. There is also sexual activity that involved an adult female that’s occurring on duty as well,” Batton said.

That other woman is 40 years old. She told detectives that she met Pross online and the two would occasionally meet up behind a 7-Eleven in Pikesville. According to charging documents, she told detectives that Pross was in uniform and he took cell phone pictures of her in handcuffs, lying naked on his police cruiser.

“This is absolutely behavior that this agency does not condone. We believe that Officer Pross has let down the community,” Batton said.

When the allegations surfaced in January, Pross had his police powers suspended immediately and he was assigned to an administrative position. Detectives are continuing to investigate other allegations.

Pross posted $50,000 bail and has been released from custody.