Prosecutors said Threlkeld posed online as a 13-year-old girl named "Sara", who said she was a model for a photographer named "Josh" and referred the underage victims to him. They said he then solicited underage girls to send him nude photographs, which many victims did.
The charges involve 80 victims, ages 11 to 17, from six California counties, including Riverside, Orange, San Bernardino and Los Angeles, as well as 15 other states as far away as New York and Florida.
Threlkeld is also charged with kidnap for rape and aggravated sexual assault of a minor. He's believed to have taken a 13-year-old girl to a home belonging to one of his friends in Palm Springs reportedly for a photo shoot but instead sexually assaulted her.
He faces multiple life sentences if convicted.
The Associated Press contributed to this report.
