alleged member of the state's largest prison gang pleaded guilty in San Antonio to conspiracy in a sprawling case that accused the gang of up to 20 unsolved killings.Federal prosecutors say more pleas are expected.They say Michael Vargas was a captain in the Mexican Mafia gang. His plea resolves allegations involving murder, drug trafficking, extortion, robbery, racketeering and related crimes. He'll be sentenced to 20 years in prison under the plea agreement.A second defendant, Ray Carrasco, has already signed a plea deal. Prosecutors say some of the remaining 20 defendants in the case are expected to follow suit.Authorities accuse members of the Mexican Mafia of peddling heroin and cocaine and taxing other drug dealers in some San Antonio neighborhoods. Up to 20 unsolved murders are attributed by federal prosecutors to the prison gang.
