The attorney general of California on Tuesday announced felony charges against a man found with a large cache of illegal firearms at his residence in Azusa, including machine guns, silencers and tens of thousands of rounds of ammunition.

Officials say the incident underscores the importance of the state’s Armed Prohibited Persons System, which identifies people who lawfully procured firearms and later became prohibited from owning or possessing them.

“In our efforts to retrieve just one gun from a prohibited individual, we found dozens of illegal weapons and thousands of rounds of ammunition,” Attorney General Bonta said in a statement Tuesday.

The man is alleged to be legally barred from owning weapons due to a mental-health based prohibition and was listed in the database as owning one firearm, the statement said. Agents from the California Department of Justice’s Bureau of Firearms initially contacted the man at his residence to retrieve his outstanding firearm but were denied entry.

After obtaining a search warrant, agents found four machine guns, seven assault weapons, a short-barreled rifle, four suppressors/silencers, six handguns, one shotgun, four rifles, 54 lower receivers/frames, 41 standard capacity magazines, 87 large-capacity magazines and approximately 35,000 rounds of miscellaneous ammunition, the statement said.

The man was arrested on Jan. 25 and charged with multiple felonies. He was arraigned last week in Los Angeles County Superior Court, Pomona.

Tracking system unique to California

In 2006, California became the first and only state in the nation to establish a system for tracking firearm owners who fall into a prohibited status, according to the attorney general’s office.

Under the system, people with a prohibited status include those who were convicted of a felony or a violent misdemeanor, were placed under a domestic violence or other restraining order or suffer from serious mental illness.

“California is the only state with a program functioning to disarm armed and prohibited people,” said Daniel Webster, director of the Johns Hopkins Center for Gun Violence Solutions. “The case in point here underscores the relevance to public safety.”

The California Department of Justice did not immediately respond to a request for comment on how many times the Armed Prohibited Persons System has been used since its launch and how many firearms are outstanding. The Violence Prevention Research Program at the University of California, Davis, is currently evaluating the system.