A teacher who taught for three decades at Miramonte Elementary School in South L.A. has been arrested and charged with lewd acts on 23 children for allegedly tying them up, placing giant cockroaches on their faces and possibly feeding them his semen from a spoon.

Mark Berndt, 61, was taken into custody Monday after a nearly yearlong investigation by the L.A. County sheriff’s special victims unit that began when a photo processor turned over pictures of some of the alleged acts to authorities.

Capt. Mike Parker of the Los Angeles Police Department said the victims identified so far are 23 boys and girls aged 7 to 10 who had contact with Berndt between 2008 and 2010.

Investigators recovered photos from the processor and Berndt’s home that allegedly showed the young students bound and blindfolded and some with large Madagascar cockroaches crawling on them inside the school setting.

Some girls were allegedly photographed with a blue spoon holding a white substance near their mouths.”Early in the investigation, special victims bureau detectives recovered a blue plastic spoon and an empty container from the trash within the suspect’s classroom,” Parker said. “The recovered items tested positive for semen.”

Through further investigation, the suspect’s DNA was obtained and tested, and officials said it matched that of the DNA found on the spoon and container.

Parker said that, so far, 10 children in the photos recovered have not been identified. More than 80 children and staff have been in interviewed. Miramonte Elementary is in the Florence Firestone unincorporated area of Los Angeles.

Berndt was fired in March and was being held Tuesday in lieu of $2.3 million bail.