The cause of the Bally Fire in Gilroy has been determined to be from the use of illegal fireworks, and four teen boys were deemed responsible, according to the Gilroy Police Department.
The boys are 14-15 years old, police said. They were issued a Juvenile Contact Report and released into the custody of their parents.
The case has been sent to the Santa Clara County Juvenile Probation Department for review and prosecution, police said.
Witnesses had said they saw a group of boys playing with fireworks before the fire started Sunday.
Despite the arrests, the investigation is still open, police said. Anyone with information regarding this investigation is encouraged to contact Arson Investigator Mitch Madruga at (408) 846-0350.
The Bally Fire was at 100 percent containment as of Thursday, fire officials said. It had burned 100 acres near Ballybunion Court in Gilroy.