SAN JOSE — A San Jose police sergeant is on paid administrative leave for an arrest earlier this month where he allegedly masturbated in his car on a Redwood City street and followed a woman who then took photos and reported him to police, authorities said.

James Rainey Mason, 48, of San Carlos, has been charged with two misdemeanor counts, one of indecent exposure and one of engaging in a lewd act, stemming from a Sept. 4 incident in the 1200 block of Woodside Road.

San Jose police spokesman Albert Morales confirmed Mason, 13-year SJPD veteran, is on leave and said the department is “monitoring the criminal investigation.”

“It’s an unfortunate situation, and we are disappointed to hear about the allegations against Sgt. Mason,” Morales said.

Mason also serves as vice chairman and police representative for San Jose’s police and fire pension board. He could not be immediately reached for comment Wednesday; calls to listed telephone numbers for him went unanswered.

San Mateo County District Attorney Steve Wagstaffe said police reports indicate a 39-year-old woman was walking on the sidewalk in the area around 5:15 p.m. when she saw a parked car and a man sitting in the driver’s seat, “masturbating with his privates completely exposed.”

Wagstaffe said the woman reportedly kept walking, and the driver started up the car and pulled forward “so he could be alongside her again, and he is still exposing himself.”

“The victim was very scared,” Wagstaffe said.

When the woman pulled out her cellphone to take pictures of the man, the man put the car into gear and drove away. But not before the woman had recorded images of both the driver’s face and the vehicle’s license plate, Wagstaffe said.

Redwood City police investigated the report and the woman identified Mason out of a photo lineup. On Sept. 11, Mason was booked then released on $15,000 bond.

Contact Robert Salonga at 408-920-5002. Follow him at Twitter.com/robertsalonga.