They fear there could be more young victims out there.
David Martz better known as math teacher Mr. Martz is under arrest for exposing himself to a 13-year-old boy in a public restroom. Police will only describe some of the explicit details.
"Mr. Martz turned around masturbated in front of the kid and the boy and left immediately," said Det. Lt. Ray Cote with Nassau County Police.
It allegedly happened in a bathroom at the Roosevelt Field Mall according to police, Saturday afternoon. They say Martz then followed the 13-year-old asking him if he wanted to go somewhere. instead the male victim ran to tell his mom helping store security and cops make a quick arrest. An arrest that they say may be overdue.
"He indicated this is not the first time he's done this and he's done this in the past," added Det. Lt. Cote.
Martz has been employed as a math teacher at Turtle Hook middle school in Uniondale for eight years. school officials sent a statement saying "The district has taken immediate action and has administratively reassigned the teacher to his home pending further investigation."
Parents say they're worried about their own kids now.
"You never know with sick people like that you never know," said Mark Martinez.
Noone answered the door at Martz' home. Police say he has a wife, two children under the age of two.
Police say Martz also taught at the boys and girls club in Oyster Bay for more than a decade.
Anyone with information on Martz should call crime-stoppers at 1-800-244-tips.