WILKES-BARRE, Pa. (AP) — A northeastern Pennsylvania police officer has been arrested on charges that he sexually assaulted four women while on duty and threatened the women to keep quiet.

Wilkes-Barre Officer Robert Collins says he plans to fight the charges, telling a judge he passed a lie-detector test.

The 53-year-old was arrested after his shift ended Tuesday. He was charged with three counts of rape, four counts of witness intimidation, and other offenses alleged in 2013 and 2014. He was ordered jailed on $125,000 bail.

Prosecutors allege that in three cases, Collins put women into his police car after finding small amounts of drugs or drug paraphernalia and forced them to perform oral sex by threatening arrest, and that in the fourth case he forced a woman into the car, locked the doors, and assaulted her.

Collins has been suspended.