SAN FRANCISCO (CBS SF) — A San Francisco man who taught film production and screening classes to young children in Marin County has been arrested on child pornography charges, police said Thursday.

John Morrison, 71, was arrested at his home on Newton Street in San Francisco’s Crocker Amazon neighborhood on Monday after a search turned up numerous devices with hundreds of videos and images, including ones of minors involved in sex acts with adults, police said.

Police said they obtained a warrant to search Morrison’s home after launching an investigation in November into an individual who was uploading and trading child pornography through a messaging app. The investigation traced the source of the pornography to his home.

Morrison teaches film production and screening classes to young children and is also the education director at a film institute in Marin County, police said. His involvement in children’s programs is ongoing.

According to court records, Morrison has been charged with one count of possession of child pornography and three counts of distribution of child pornography, all felonies.

The possession charge includes allegations that he had more than 600 images, including more than 10 depicting children under the age of 12 and some depicting acts of sexual sadism or masochism.

Morrison was released from custody after posting bail and is scheduled to be arraigned at 1:30 p.m. Friday.

Anyone with further information on Morrison or who has had any suspicious contact with him is asked to call the department’s Special Victims Unit at (415) 558-5500.

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