A 19-year-old Tampa man pled guilty to possession of child sexual abuse material after law enforcement found more than 8,300 images and videos of child sex abuse material on his digital devices.The U.S. Attorney's Offices said Jack Rocker, 19, was a member of "a network of racially or ethnically motivated violent extremists called '764.'" According to the US attorney, the group used social media platforms as "mediums to support possession, production, and sharing of extreme gore media and CSAM."The FBI seized Rocker's cellphone, thumb drive, and laptop, where they discovered the images and videos of brutal child sex abuse material.Rocker faces a maximum penalty of 20 years in federal prison as a result of his plea.