SANTA CLARA — Federal agents have arrested a felon they suspect owned and was making guns as a member of a local militia, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The ATF, assisted by Santa Clara police, served a search warrant on a home in the 800 block of Benton Street on Tuesday morning. In addition to arresting 41-year-old Juan Gutierrez, authorities seized two assault-style weapons, a pistol, a .308 rifle, and more than 1,000 rounds of ammunition according to an ATF news release. At least some of the firearms had no serial numbers.

By law, anyone convicted of a felony is barred from possessing firearms.

The ATF said it had been investigating Gutierrez since early March, and said he is a member of the California State Militia, South Bay Platoon. The agency provided no other details about the case, which is being prosecuted by the U.S. attorney’s office.