On July 15, 1976, three men kidnapped 26 children and their school bus driver and held them captive in a buried trailer.
James Schoenfeld, his brother, Richard, and a friend, Fred Woods, were given life sentences after pleading guilty to kidnapping charges.
The men spent 18 months devising the plot and planned to ask for a $5 million ransom for the children, who ranged in age from 5 to 14.
The hostages were taken from Chowchilla to a quarry near Livermore and kept inside the ventilated trailer stocked with mattresses, food and water. The driver and children dug their way out and escaped unharmed after about 16 hours.