SAN FRANCISCO (CBS SF) – A San Francisco police officer was arrested Monday on sexual assault charges following an investigation by internal affairs, according to authorities.

San Francisco Police Department officials said that the investigation into Officer Justin McCall began in September of last year when the Internal Affairs Criminal Division was notified of possible criminal conduct committed by McCall while off duty.

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When the investigation began, McCall, age 30, was removed from his assignment in the field and assigned to a position where he did not have contact with the public.

Upon completion of the investigation, an arrest warrant was issued for McCall, a San Francisco resident and a four-year veteran of the SFPD. On Monday at approximately 1 p.m., McCall was arrested and booked into San Francisco County Jail.

McCall faces charges of sexual assault when the victim is prevented from resisting by an intoxicating substance and for sexual assault of a victim who was unconscious or asleep. McCall has been suspended without pay pending trial.

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In a press release, the San Francisco Police Department thanked the District Attorney’s Office for its assistance during the investigation.

“The public’s trust is of the utmost importance to the members of the SFPD and the Department will continue to work hard to build and maintain this trust,” the press release read.

While current San Francisco Police Chief William Scott has said Department members will continue to hold each other accountable and will act swiftly to report any behavior that might bring dishonor to the police department and the City of San Francisco, the arrest marked the latest officer on the force getting into legal trouble.

Last July, Officer Joshua Enea, a 37-year-old Antioch resident and 10-year veteran of the department, was arrested on suspicion of felony possession of child pornography following an investigation.

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In September of last year, Officer Joel Babbs was arrested on misdemeanor charges of using false vehicle registration stickers and filing a false police report, according to authorities.