A 19-year-old online leader of a nihilistic extremist group was sentenced Wednesday to 40 years in federal prison for a horrific campaign of racketeering and child sexual exploitation aimed at sowing social chaos.

Alexis Aldair Chavez, also known online as "Zack" and "Zack8884," was also ordered to undergo a lifetime of supervised release and pay $10,000 in restitution.

Federal prosecutors said Chavez served as an administrator for "8884," a digital network tied to the larger "764" Nihilistic Violent Extremist (NVE) group.