"the most important event in my life. If I had never done anything since . . . my involvement in Sleepy Lagoon would justify my existence."

Alice McGrath, a lifelong activist who first gained fame as a champion of the wrongly convicted young Mexican Americans in the 1942 Sleepy Lagoon trial, has died. She was 92. McGrath's role in the infamous trial was celebrated in Luis Valdez's play "Zoot Suit," which debuted at the Mark Taper Forum in 1978 and was made into a movie in 1981.

"She was one of the heroines of the 20th century," said Valdez, who remained a friend over the years. "In Los Angeles, I can't think of many people who surpass her influence."

McGrath was 24 when, recovering at home from a bout of pleurisy, she was visited by a friend who asked for some administrative help. Attorney George Shibley was defending 22 Mexican Americans, ages 17 to 21, who were charged with killing a young Mexican farmworker near a swimming hole in southeast L.A. County known as Sleepy Lagoon. Shibley needed someone to write summaries of the daily proceedings of the trial, which would later become known as one of the most racist in local history.

The defendants, dubbed "zoot suit gangsters" by a xenophobic press after the long coats and pegged pants that were popular among Mexican Americans, were being tried en masse. Portrayed as members of the "38th Street Gang," they were not allowed to consult with their lawyers during the 13-week trial. And in a tactic that made them look disreputable, they were not permitted to have their hair cut and were denied a change of clothes for the first month of the trial.

The judge was openly contemptuous of the defendants and their lawyers, and the all-white jury was allowed to go home at night, with access to sensationalist media coverage that focused on Mexican American delinquency.

Twelve were convicted of murder and the rest of lesser charges.

McGrath, who attended the trial after her illness subsided, was outraged, and began to volunteer with the Sleepy Lagoon Defense Committee, which lobbied for an appeal. Committee head and renowned author Carey McWilliams was impressed with her passion and named her executive director.

McGrath would become an accomplished fundraiser and speaker, at one time addressing 1,000 longshoremen in San Francisco. She regularly visited the Sleepy Lagoon defendants at San Quentin State Prison.

In 1944, an appeals court overturned the convictions, finding there was no evidence that any of the young men had been involved in the killing.

Decades later, in 1981, McGrath would tell a Los Angeles Times interviewer that the successful appeal was "the most important event in my life. If I had never done anything since . . . my involvement in Sleepy Lagoon would justify my existence."