JACKSONVILLE, Fla. -- An ex-Marine who has worked as an ROTC instructor at Ribault High School for the past five years appeared in court Saturday morning and was being held on a $500,000 bond.

John Harvey, 62, was arrested this week and charged with five counts of possession of child pornography.

Harvey went to work at Ribault in 2004 after retiring as a colonel from the U.S. Marines.

Assistant Attorney General Maureen Horkan said investigators found over 100 photos of children between 5 years old and teenagers, and 38 movies containing images of children/minors engaged in sexual activity on Harvey's computer.

Horkan said investigators with the Cyber-Crime unit found Watson during an ongoing investigation into people trading child pornography over the Internet.

According to the arrest report, Watson admitted to detectives that he had downloaded and viewed pornographic movies on his computer. The report said he told investigators, "He knew it was illegal, and did it anyway."

Watson was removed from the classroom and then removed from the school to a nonteaching position as soon as the school system was notified of his arrest.

State cyber-crime investigators said parents should not be surprised that an ROTC instructor and retired colonel is accused of such a crime.

"We have found individuals in all walks of life," Harvey said. "People with higher ranks in the military, people with law degrees, doctors -- anybody is a potential suspect."