LOWELL (CBS) – A Lowell High School guidance counselor and former part-time Hampton, New Hampshire policeman is accused of flashing students on their morning school bus ride.

Fifty-four-year-old John Silva pleaded not guilty to two felony charges of lewd behavior Thursday.

“It appears to have been going on for several months now,” said Lowell Police Capt. Kelly Richardson. “He would pull up beside the bus. He would be masturbating inside the vehicle.”

Kelly said a 13-year-old girl in the bus snapped a picture of him and his car with her phone. Police traced the license plate to Silva’s Westford home.

It didn’t take long for the news to spread through the halls of Lowell High School.

“He’s really funny and he’s smart and he’s been a counselor for a lot of years,” said one student. “It’s all over Facebook, Twitter, everything,” said another.

Silva worked part-time for Hampton Police during summer months for nearly a decade.

He’s worked at Lowell High School for 15 years. He’s now on paid administrative leave.