Former McMartin prosecutor Glenn Stevens was granted immunity by Los Angeles Superior Court Judge William Pounders, who ordered him to return to court Tuesday to begin answering questions about his role in the Manhattan Beach child molestation case. Stevens resigned from the district attorney's office last year under pressure from his superiors. Both the state attorney general and the Los Angeles city attorney had been considering criminal charges against Stevens alleging obstruction of justice and aiding the defense. But the agencies joined in asking Pounders to offer Stevens immunity in exchange for his testimony about allegations that the district attorney's office handled the case improperly and suppressed evidence vital to the defense. Defense attorney Dean Gits, who represents Peggy McMartin Buckey, asked that her trial be severed from that of her son, Ray Buckey, on grounds that a combined trial would create "potential prejudice" against her because the evidence against him is stronger.