SAN ANTONIO -- Members of the Bexar County Sheriff's Department Gang Unit arrested who they called the newly-crowned leader of the prison gang, the Mexican Mafia, KSAT 12 News reported in an exclusive report Thursday night.

Joe Peña, 31, was pulled over at Goliad and Southeast Military Drive after he failed to use his left turn signal, authorities said. Peña was arrested for possession of marijuana. He also had $2,300 in cash.

Peña posted bond and was released from the Bexar County Jail. But his arrest gave deputies valuable information about the suspect's activities and his new associates.

"Eventually, all that is going turn up into a big conspiracy case," said Bexar County Sheriff's Department Chief Deputy Raymond Treviño. "These people are not rocket scientists."

Treviño said Peña, who had a clean record prior to his arrest, seized control of the reputed prison gang following the arrests of an alleged vice president and general during a roundup of the mafia's leadership in August.

"They regenerate and they just plant new seeds," Treviño said.