Petrash faces a maximum sentence of two years in jail and sex offender registration when he's sentenced Nov. 18 at the Harbor Justice Center, Newport Beach.
On Aug. 24, 2009, Petrash took his son to a dental appointment. While he waited for his son in the empty reception room, Petrash was accused of pulling up his shorts and exposing his penis to the receptionist.
The receptionist reported the incident to the Orange County Sheriff's Department. After an investigation, Petrash was arrested Oct. 1, 2000 at Serrano Intermediate School in Lake Forest.
After seeing media coverage of the arrest, a fellow teacher in the same school district contacted police.
On May 8, 2009, Petrash was attending a Saddleback Valley Unified School District event. He followed the fellow teacher into a hotel restroom and entered her restroom stall.
Petrash stood between the fellow teacher and the door and exposed and rubbed his penis. He put his finger over his mouth, indicating she should be quiet. The victim was able to escape the restroom stall.
During the trial, Petrash claimed he did not expose himself to the receptionist and said the fellow teacher had agreed to go with him into the men's restroom to expose her breasts to him.
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