'Such extreme steps': San Jose killer intricately planned rail attack with a simple motive in mind

Samuel Cassidy prepared for years to unleash his rage.

He had weapons. He read up on terrorism and manifestos. He harbored bomb-making materials. He rigged his home to go up in an inferno as he set out to kill nine fellow employees at a light-rail hub in San Jose.

While he plotted intricately for a mass attack, appearing like a terrorist on a mission, his motive was much simpler: He just hated his co-workers.

That's the picture painted so far by law enforcement as detectives try to understand the pent-up animosity that Cassidy appears to have kindled for a decade against the people he worked alongside.

Cassidy, described by those who knew him as having alcohol issues, for years talked about his hatred of his workplace at the Santa Clara Valley Transportation Authority (VTA) light rail hub. The details make clear the suspect employed tactics not routinely seen in mass shootings.

"It really stands out when you have an individual like this who goes to such extreme steps," said Ed Davis, a former commissioner for the Boston Police Department who helped lead the investigation into the 2013 Boston Marathon Bombing. "You have people with these burdens of something that was done to them and they fixate on them and it ends up turning into a decade-long vendetta."

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Exes say Cassidy had 'two sides,' talked about workplace violence

Long before Wednesday's attack, Cassidy ranted about his job and co-workers — even threatening to kill.

Two women — an ex-wife of 10 years and an ex-girlfriend — offered a glimpse at Cassidy's past, detailing his anger and alcohol issues, along with previous threats of workplace violence.

Cecilia Nelms, who was married to Cassidy for about 10 years before they filed for divorce in 2005, told The Mercury News Cassidy had "two sides."

She said he often was angry at co-workers and about his assignments at work. She told the outlet Cassidy thought the VTA was unfair with its work assignments, though she said she hasn't spoken with him in about more than a decade.

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"He had two sides," Nelms told The Mercury News. "When he was in a good mood he was a great guy. When he was mad, he was mad."

She told the Associated Press he'd "dwell on things" and had talked about killing people at work more than a decade ago.

"I never believed him, and it never happened. Until now," Nelms said through tears.

Another woman who dated Cassidy accused him in court documents in 2009 of rape and sexual assault. The filing, obtained by The Mercury News, also includes accusations that Cassidy had severe mood swings and suffered from alcohol abuse.

Neighbors of Cassidy described him as quiet, strange and a bit of a loner, saying he didn't talk to others and seemed unfriendly.

Doug Suh, who lives across the street from Cassidy, told USA TODAY Cassidy had lived in the area for 20 years but despite his roots there, never wanted anything to do with his neighbors. He said he'd tried to talk with Cassidy multiple times, saying hello and offering other pleasantries, but wouldn’t get much of a response.

"Every time I say hi, he’s ignored me," Suh said. “I was surprised though...I didn’t think he was going to ... kill people like that."

Suh added to The Mercury News, Cassidy was "lonely" and "strange." He never appeared to have visitors.

Once, Cassidy yelled at him to stay away as he was backing up his car. “After that, I never talked to him again," Suh told the newspaper.

Signs of preparation 5 years ago

In 2016 — five years before the mass attack — Cassidy was stopped on a trip back from the Philippines by U.S. Customs and Border Protection.

A Department of Homeland Security memo from the stop, which was obtained by The Wall Street Journal, includes that an officer found Cassidy had "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."

A Biden administration official said he saw the memo and confirmed its contents to The Associated Press.

The memo doesn’t say why Cassidy was stopped after his 2016 trip. It notes the gunman had a "minor criminal history" and cites a 1983 incident where he was arrested in San Jose and charged with "misdemeanor obstruction/resisting a peace officer."

A spokesperson for the Department of Homeland Security declined to comment on the memo to USA TODAY. The Santa Clara County Sheriff's Office, which is leading the investigation into the shooting, did not respond to repeated questions about whether they were notified about the 2016 stop or investigated Cassidy afterward.

Gunman targeted victims, set timer to set his home on fire

Cassidy left his home around 5:39 a.m., armed with a duffel bag and what experts say was a plan to never return.

Before he left, he set a timer or slow-burn device to set his two-story on fire, Santa Clara County Sheriff Laurie Smith said. The fire was reported minutes after the first 911 calls came in about the shooting at the rail facility.

Footage captured by news helicopters showed law enforcement sifting through debris in the backyard of the beige home throughout Wednesday afternoon. The back of the home appeared to have the most visible damage with the roof charred and debris thrown in the yard.

"Everyone of these killers are different but it's clear he wanted to express his rage on others but also wanted to destroy himself -- and that included his home," said Dr. Ziv Cohen, a forensic and clinical psychiatrist who consults on murder cases and serves as an expert witness in criminal trials.

Cohen noted it's possible the suspect may have been attempting to destroy evidence, but it was clear he didn't plan to return. "I don't really think I remember a specific example like this one where a person destroyed their home," he said.

Cassidy fired 39 shots during his rampage through two buildings at the sprawling VTA hub and appeared to target some of the victims, Smith told the Associated Press in an interview.

Smith said the shooter told at least one person: “I’m not going to shoot you” during the attack. The gunman then shot other people before he shot himself as deputies closed in.

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Three handguns, 11 illegal high-capacity magazines and explosives

As authorities cleared the rail yard Wednesday, they found an assortment of what appeared to be bomb-making materials in Cassidy's locker — forcing a lockdown of the area and bomb technicians to sweep the large complex.

Smith told NBC's "Today" Cassidy's locker had “materials for bombs, detonator cords, the precursors to an explosive,” Smith said.

The Sheriff's Office told The Mercury News the contents of the locker were later deemed to not be dangerous and no actual explosive devices were discovered.

Sheriff’s Deputy Russell Davis said Cassidy had three semi-automatic 9mm handguns along with 32 high-capacity magazines loaded with additional ammunition.

In California, it is illegal to buy magazines that hold more than 10 rounds. However, if Cassidy had obtained them before Jan. 1, 2000, he would be allowed to have them unless he was otherwise prohibited from possessing firearms.

Despite accusations from two women — an ex-wife and ex-girlfriend — that Cassidy was violent, had alcohol problems and was sexually abusive, there was nothing in public records to indicate Cassidy ever got in trouble with the law, meaning he likely was legally able to obtain a firearm.

Authorities have yet to say whether that was the case or when Cassidy obtained the firearms. He received a traffic ticket in 2019 and sheriff’s officials said they were still investigating his background. His social media presence - if he had one - is not apparent.

Signals often aren't enough to stop a killer

Cohen noted the details, from the accusations of violence to his lengthy vendetta against his workplace, signal Cassidy fits the typical mass shooter profile.

He detailed the alcohol abuse, sexual violence, signs of lengthy planning and built-up hatred are often found in mass killers. But, he said, there are plenty of people across the U.S. who show similar warning signs and do not commit mass murder.

Cassidy, he said, appeared to want to make a statement in Wednesday's attack and attempted to employ multiple factors, from potential bomb-making materials to a fire, to ensure his rage was expressed.

"Clearly, he appeared to be experimenting with some of these materials," Cohen said. "We should be very thankful it wasn't worse."

Both Cohen and Davis, the former Boston Police Commissioner, said the case reminded them of the 2012 Aurora, Colo. movie theater shooting. The gunman in that attack, which killed 12, attempted to booby trap his home before the shooting.

"When you deconstruct what happened, you realize that there were a lot of warning signs with people like this," Davis said. The problem, though, is law enforcement comes into contact with many people who have similar signs.

"The challenge is we live in a free society. We cannot simply take action against someone who is showing indicators that something might happen," he added. "It's hard because a crime has to happen before an arrest. You can't always anticipate behavior."

Contributing: Grace Hauck, USA TODAY; Angelica Cabral, The Salinas Californian, part of the USA TODAY Network, who reported from San Jose

This article originally appeared on USA TODAY: San Jose shooting suspect Samuel Cassidy intricately planned attack