LOS ANGELES (AP) — Federal prosecutors say the leader of the so-called “Oxy Bandits” crew has been convicted of organizing armed robberies of oxycodone at 15 independently owned pharmacies across Southern California.

A judge found Tyrome Lewis guilty of eight felony charges. Prosecutors say the 26-year-old conspired with others to target “mom and pop” pharmacies in Los Angeles, Orange and Riverside counties. Lewis faces life in prison when he’s sentenced on September 23. The case is part of a broader investigation of armed pharmacy robberies by the FBI and the LA County Sheriff’s Department.

Prosecutors have charged 21 individuals, with 19 convictions. Two defendants are awaiting trial.