SACRAMENTO, California (AP) -- Gov. Jerry Brown has blocked parole for a former leader of the notorious Mexican Mafia prison gang who has turned on his former comrades and now aids law enforcement.

Brown announced Friday that he was blocking the release of 52-year-old Rene ``Boxer'' Enriquez.

Enriquez has been in prison since 1993 serving a sentence of 20 years-to life in prison for two murders, multiple assaults and conspiracy to traffic in controlled substances.

He drew attention last month when elite Los Angeles Police Department officers cleared a downtown Los Angeles building so Enriquez could speak to a gathering of police chiefs and business leaders.

Enriquez spoke about the growth and operations of a prison gang that has evolved into a transnational criminal enterprise.