Authorities say the elementary school teacher told children that it was a game. Once inside his third-grade classroom, they said, he blindfolded them, gagged them and let cockroaches crawl on their faces.
And then, Mark Berndt photographed them, creating hundreds of images that would eventually lead to his arrest, police said.
On Tuesday, Berndt, 61, was sitting in jail on charges that he committed lewd acts on 23 boys and girls, ages 6 to 10, between 2008 and 2010. None of them complained about Berndt's behavior, authorities said.
Police and school officials only learned of it when a film processor found Berndt's photos more than a year ago. Since the discovery, the school district fired Berndt and police put him under surveillance.
"If it wasn't for the film processor, this could still be continuing today," said Lt. Carlos Marquez of the Los Angeles County Sheriff's Department.
Berndt was arrested Monday at his home in Torrance and was being held on $2.3 million bail.
Some parents who were picking up their pre-kindergarteners at the school on Tuesday complained that officials at Miramonte Elementary School in South Los Angeles should have notified them when the photos were found.
"My concern is why, if the principal knew this in advance, why didn't he inform us?" said Gloria Polanco, the mother of a second- and a third-grader. "How long has he been doing this?"
The investigation began after the film processor, who is required by state law to report suspicions of child abuse and molestation, turned over some 40 photographs to authorities.
Searches of Berndt's classroom and home turned up about 400 photographs featuring children, though the number of pictures may not be the same as the number of kids. At least 10 youngsters in the photos have not been identified.
Some photos showed Berndt with his arm around children or his hand over their mouths. Some photos showed children with live bugs the size of hissing cockroaches on their mouths or faces.
Others depicted girls with what appears to be a spoon up to their mouths as if they were going to ingest a clear-white liquid. Children were fed Berndt's semen from a spoon or on cookies, Marquez said.
Kids reported being fed something distasteful. A blue, plastic spoon and container found in the trash in his classroom tested positive for his semen, authorities said.
Police recommended the children in the photos be tested for sexually transmitted diseases.
Advertisement