NEW: Middle school teacher accused of using AI to generate CSAM of kids between the ages of infant & 12 years old before pleasuring himself to the images at work.

47-year-old Matthew Lund was a science teacher at Andersen Middle School in Omaha, Nebraska.

Prosecutors say they found 423 artificially generated images.

"[There are] 104 files consistent with CSAM … depicting ranging from infant to approximately 12 years old," prosecutors said.

"The defendant then admitted to generating the [CSAM] of prepubescent children and m*sturbating to them while at work, at which he is a middle school science teacher."

Lund is facing a maximum sentence of 50 years.

Horrific.