SANTA CRUZ, Calif. (KRON) — As shock from the San Jose mass shooting turns to grief and reflection, California’s law enforcement leaders say they want to have an honest conversation about balancing the right to bear arms under the Second Amendment with protecting the public from mentally unstable gun owners.

Sam Cassidy was armed with three semi-automatic handguns and high capacity magazines when he fired 39 shots, killing nine of his coworkers at the Valley Transportation Authority rail yard downtown.

The FBI and Santa Clara County Sheriff said it appears that Cassidy owned the handguns legally, but the high-capacity magazines violated California law.

Photos of Sam Cassidy provided by Cecilia Nelms

Cassidy had depression and anger issues that he’d verbally unleash at home, his ex-wife, Cecelia Nelms of Santa Cruz, told KRON4.

“He would scream and yell. I was getting to the point where I was starting to feel kind of unsafe,” Nelms said.

She had not spoken with her-ex husband in 15 years and did not recall Cassidy owning any firearms when they were married.

“I never knew that side of him liking guns,” she said. Nelms left the marriage when Cassidy’s mood swings became worse.

Lawmakers and police chiefs are reflecting on what went wrong and what California can do to prevent the next mass shooting.

One of the VTA shooting victims was from Santa Cruz: Michael Rudometkin.

VTA shooting victim Michael Rudometkin / (Facebook)

His mother, Rose Rudometkin, told KRON4: “It is with heavy hearts that we lost our son to a ruthless disgruntled employee of VTA.  Our son was attending a union meeting at the time this occurred. He had just turned 40. He would give his last penny and shirt off his back. Anyone could call him for help and he’d be there.”

“What a horrific event. I think these things are stop-able,” Santa Cruz Police Chief Andy Mills said.

To stop future mass shootings, law enforcement experts say critical communication has to come from the friends and family of mentally unstable community members who make threats in private conversation about wanting to harm others.

“If we work with the community, work with people who have access to people who are maybe on the edge, then we can intervene a little bit more quickly and make sure that this does not happen,” Mills said.

New photos shared by the Santa Clara County Sheriff’s Office Friday revealed what was inside Cassidy’s home on Angmar Court: Multiple cans of gasoline, suspected Molotov Cocktails, 12 firearms, and about 22,000 rounds of ammunition.

Ammunition found inside Cassidy’s home. (Santa Clara County Sheriff’s Office)

The Sheriff’s Office said its investigators determined that the VTA mass shooting was a “planned event,” and the gunman “was prepared to use his firearms to take as many lives as he possibly could.”

Cassidy did not have a criminal record.

According to the Wall Street Journal, Customs and Border Protection detained Cassidy in 2016 when he was returning from a trip to the Philippines and he possessed a book about terrorism.

The WSJ obtained a memo by U.S. Customs officers stating that Cassidy possessed “books about terrorism and fear and manifestos…as well as a black memo book filled with lots of notes about how he hates the VTA,” when Customs and Border Protection detained him in 2016 after a trip to the Philippines.”

If alerted by friends or family members of a potentially violent person, law enforcement agencies can use threat management teams to intervene. With permission from the courts, police can take a mentally unstable person’s guns away temporarily until they receive mental health services, Mills said.

“We can take these threats seriously. People have to listen to what their friends and family are saying, what their colleagues are saying if they are issuing threats. If there is a lot of stress in their life, call the police,” Mills said.

Vigil for victims

“So far it’s been very successful for us and other agencies in our area. I don’t think this will stop all shootings But it may stop some,” Mill said.

A neighbor’s surveillance camera captured video of Cassidy moments before the shooting Wednesday morning. The video shows the 57-year-old man loading a large duffel bag into his white truck as he left for work around 5:40 a.m.

High-powered assault rifles are often weapons of choice for killers bent on taking down as many victims as possible. In the case of Cassidy, even handguns proved to be tragically lethal. Nine victims were fatally wounded by the time Cassidy killed himself as police ran toward the threat.

Sheriff Laurie Smith said, “The first team through the door was the Sheriff’s Office and San Jose Police Department. They’re my true heroes. There was active shooting going on at that time.”

Mills said creating policies that keep firearms out of the hands of potentially violent people is key.

“Firearms are weapons that are designed to kill. And so you have to make sure that they are not in the hands of those who are included to do so. Now how that interacts with the Second Amendment is the big question. How do we thoughtfully keep handguns out of the hands of people who are going to hurt others but yet protect people’s right to possess and bear firearms? I think that is a do-able policy,” Mills said.

“Obviously we have a problem. It’s going to take a lot of give and take, negotiation. And it’s going to take really sitting down and talking with one another and assessing what are we doing as a nation and as a community,” Mills said.