Michael “Rab” Garrett dies of synthetic marijuana overdose.

According to the New York Daily News, shortly after Michael “Rab” Garrett was convicted of murder, the rapper and co-leader of the Together Forever Mafia was found dead due to a drug overdose.

His death at the Metropolitan Detention Center has been ruled accidental, following an autopsy.

“I’m incredulous. He was in federal custody. That’s not like Rikers Island or a county facility,” Garrett’s former lawyer, James Lisa said while speaking with the New York Daily News.

In addition to Lisa, prison consultant Cherie Nolan also expressed shock at Garrett dying from a drug overdose while in a federal jail.

“The feds usually do a good job of keeping contraband out,” Cherise Nolan said. “The security in place for people going into and out of facilities, and the performance of staff, has greatly improved.”

Following their trial, Garrett and another Together Forever Mafia member, Paul Rivera were convicted of racketeering, murder, sex trafficking of underage prostitutes, and drug trafficking.

Garrett, who faced life without the possibility of parole, had yet to receive his sentencing.

Last year, Together Forever Mafia made headlines when a judge allowed YouTube music videos to be used against Garrett and Rivera, during their trial.