(CNN) - Arizona Department of Public Safety detectives arrested one of their own troopers Tuesday on charges of sexual abuse, extortion, kidnapping, harassment and fraud, AZDPS Col. Frank Milstead said at a news conference.
Tremaine Jackson, 43, an AZDPS trooper for about 13 years, used his position of authority to "bargain leniency for favor," Milstead said.
"The Arizona Department of Public Safety is a proud and venerable organization with a storied past," Milstead said. "Most of the employees serve Arizona with pride and integrity. ... When one of our own betrays public trust or breaks the law, we respond swiftly and without regret."
Jackson most recently worked in the department's Metro Motors District. Officers began an investigation on May 19 after a woman complained that Jackson made inappropriate comments to her, Milstead said. A second complaint from a different motorist came June 11, alleging that Jackson sexually assaulted a woman during a traffic stop, Milstead said. He was placed on administrative leave that day, Milstead said.
Jackson has since been terminated, Sgt. Kameron Lee, public information office supervisor for the department said Tuesday.
It is unclear if Jackson has retained a lawyer.
So far, investigators said they have identified eight victims. They believe there are more and have set up a hotline and website for other victims to come forward.
Authorities said Tuesday that Jackson would be booked into the Maricopa County Fourth Avenue Jail on charges including sexual abuse, sexual extortion, unlawful sexual conduct, unlawful imprisonment, kidnapping, fraudulent schemes and practices and tampering with a public record.
"The temerity of Trooper Jackson is horrifying," Milstead said. "Our job now is to respond appropriately."
The Arizona State Troopers Association declined to comment.