MILLBRAE (CBS SF) — A man was arrested for indecent exposure after allegedly masturbating in front of a 16-year-old victim at a 24 Hour Fitness gym in Millbrae, police announced on Sunday.

The incident occurred on Thursday, Mar. 28 shortly before midnight. Deputies from the Millbrae Police Bureau of the San Mateo County Sheriff’s Office were dispatched to the gym following reports of indecent exposure.

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The teenage victim was with a family member at the gym. While he was in the locker room, the suspect exposed himself to the victim and began masturbating, police said.

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The victim instantly alerted the gym’s staff, who then made contact with the suspect and made sure he didn’t leave until deputies arrived.

The suspect, 49-year-old Thomas Myint of Daly City, was booked into Maguire Correctional Facility on misdemeanor charges of indecent exposure and annoying/molesting children.

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Anyone with additional information about the crime are encouraged to call the Millbrae Police Bureau at 650-259-2300 or the San Mateo County Sheriff’s Office Anonymous Tip Line at 1-800-547-2700.