A Philadelphia man allegedly possessed hundreds of forms of child sexual abuse material, many involving babies and toddlers, that were traded through online groups, the Pennsylvania Attorney General's Office announced Tuesday.

Pennsylvania AG Dave Sunday said John Stachecki, 55, who lives in Center City, was arraigned on 200 charges for possessing child sexual abuse material and has bail set at $1 million. 

Members of the Attorney General's Office and Homeland Security discovered through an investigation that Stachecki was a member of "dozens of online groups — accessible only by encrypted key —  that traded child sexual abuse material," according to Sunday.

"We cannot overstate the depths of depravity that exist online, as evidenced by this investigation that uncovered an invitation-only network used to share and view child sexual abuse material," Sunday said. "I commend our partners at Homeland Security for helping to identify the defendant who was an active member of these groups, with a deviant fixation on very young children."

Law enforcement officers executed a search warrant at Stachecki's home on the 1900 block of Chestnut Street, where investigators recovered hundreds of incriminating videos and images, Sunday said. 

Edward Owens, Special Agent in Charge of Homeland Security Investigations Philadelphia, said HSI will continue to "relentlessly pursue" anyone exploiting our society's most vulnerable members.