A police officer in Oklahoma City was arrested Thursday and held at $5 million bond for sexually assaulting women aged between 34 and 57 while on duty.

Daniel Ken Holtzclaw, 27, who has been in the police force for 3 years, assaulted seven women for months, police said. The complaint stated that he raped one woman and forced three others to perform oral sex. Other complaints included sexually battery and indecent exposure, according to The Oklahoman.

Oklahoma City Police Chief Bill Citty said that, while being on duty, Holtzclaw forced women to expose themselves, fondled them and also had intercourse with one woman, the Associated Press reported. The incidents occurred during his 4 p.m. and 2 a.m. shifts, police said.

"We started the investigation and we started looking at traffic stops he had made throughout the previous months to try to identify and initiate contact with females that we knew he had stopped during that period of time ... to see if they had been sexually assaulted," Citty said.

Holtzclaw also led his victims to remote spots before assaulting them. If the victims did not obey, he would threaten them, the New York Daily News reported. 

A 57-year-old woman who said Holtzclaw forced her to perform oral sex, complained about the officer in June. "She was really, really fragile," Alitia Timmons, the woman's representative, told KOCO. "She was scared to leave her house, when she was driving and she saw a police officer drive by it would terrorize her and she has been piecing herself together."

The charges against Holtzclaw are yet to be filed, and Oklahoma County District Attorney David Prater said he expects the charges to be filed by Aug. 29.