A search warrant was served at approximately 11:35 a.m. Friday on the 2200 block of the Avenue, Concord, authorities said.
More than a dozen weapons have been found.
Some of the firearms were not “California compliant” assault ” rifles, and banned high-capacity magazines.
The 45-year-old Antonio Valadez, 46-year-old Isidor Mendiola, the 20-year-old Enrique Renteria and the 26-year-old Joseph Hernandez have been locked up.
(© Copyright by 2020, CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)