An 18-year-old Pennsylvania high school student was tracked down by police and arrested on Friday.
Derrick Jones, a student at Monsignor Bonner Catholic High School, created fake social media accounts as "Haley", a stolen identity, and reached out to boys.
Jones had at least 136 victims, according to police, and would blackmail them using nude photos they had sent him.
"They believed that they were receiving naked pictures of a teenage girl and so they were responding to Haley thinking that it was a teenage girl that was interested in them. Unfortunately, it was not," Delaware County District Attorney Jack Whelan said at a press conference.
Police expected more victims would come forward.
Jones confessed he posed as Haley to get the photos for his own pleasure.
"This information is deeply disturbing to all of us," the Archdiocese of Philadelphia said.
"Our immediate concern is for those who were or may have been victimised. Our understanding is that Delaware County Detectives have been in contact with individuals they have reason to believe could be a victim in this matter."
Jones was charged with manufacturing child pornography, possession of child pornography, corruption of minors, stalking and other crimes.