PHOENIX -- Police arrested a Flagstaff high school teacher Monday who they say had sex with students he met as a martial arts instructor, authorities said.

John Francis Pertuit, 35, was immediately placed on administrative leave after he was arrested, police said.

The investigation began when someone sent police a tip saying Pertuit was sexually involved with students he met at school and his martial arts business, police said.

According to a statement from the Flagstaff Police Department, the investigation is ongoing.

Pertuit was charged with six counts of sexual conduct with a minor, police said. His bond was set at $75,000 cash.