An employee who gunned down eight people at a California rail yard and then killed himself as law enforcement rushed in had talked about killing people at work more than a decade ago, his ex-wife said.

“I never believed him, and it never happened. Until now,” a tearful Cecilia Nelms told The Associated Press on Wednesday following the 6:30 a.m. attack at a light rail facility for the Valley Transportation Authority.

“When our deputies went through the door, initially he was still firing rounds. When our deputy saw him, he took his life,” Santa Clara County Sheriff Laurie Smith told reporters.

The sheriff’s office is next door to the rail yard, which serves the county of more than 1 million people in the heart of the Silicon Valley.

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The attacker was identified as 57-year-old Samuel Cassidy, according to two law enforcement officials. Investigators offered no immediate word on a possible motive but his ex-wife said he used to come home from work resentful and angry over what he perceived as unfair assignments.

“He could dwell on things,” she said. The two were married for about 10 years until a 2005 divorce filing and she hadn’t been in touch with Cassidy for about 13 years, Nelms said.

It was the 15th mass killing in the nation this year, all of them shootings that have claimed at least four lives each for a total of 86 deaths, according to a database compiled by The Associated Press, USA Today and Northeastern University.

At the White House, President Joe Biden ordered flags to be flown at half-staff and urged Congress to act on legislation to curb gun violence.

“Every life that is taken by a bullet pierces the soul of our nation. We can, and we must, do more,” Biden said in a statement.

Gov. Gavin Newsom visited the site and then spoke emotionally about the country’s latest mass killing.

“There’s a numbness some of us are feeling about this. There’s a sameness to this,” he said. “It begs the damn question of what the hell is going on in the United States of America?”

The shooting took place in two buildings and killed employees who had been bus and light rail operators, mechanics, linemen and an assistant superintendent over the course of their careers. One had worked for the agency since 1999.

The Santa Clara County Office of the Medical Examiner-Coroner identified the victims as Paul Delacruz Megia, 42; Taptejdeep Singh, 36; Adrian Balleza, 29; Jose Dejesus Hernandez, 35; Timothy Michael Romo, 49; Michael Joseph Rudometkin, 40; Abdolvahab Alaghmandan, 63, and Lars Kepler Lane, 63.

Another man wounded in the attack was in critical condition at Santa Clara Valley Medical Center, spokesperson Joy Alexiou said.

Singh had worked as a light rail train driver for eight or nine years and had a wife, two small children and many family members, said his cousin, Bagga Singh.

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“We heard that he chose the people to shoot, but I don’t know why they choose him because he has nothing to do with him,” he said.

San Jose City Councilman Raul Peralez said Rudometkin was a close friend.

“There are no words to describe the heartache we are feeling right now, especially for his family,” he wrote on Facebook. “Eight families are feeling this same sense of loss tonight and our entire community is mourning as well.”

The shooter had more than one gun, county District Attorney Jeff Rosen said.

It wasn’t immediately clear whether he had obtained the guns legally.

In court documents, an ex-girlfriend described Cassidy as volatile and violent, with major mood swings because of bipolar disorder that became worse when he drank heavily.

Several times while he was drunk, Cassidy forced himself on her sexually despite her refusals, pinning her arms with his body weight, the woman alleged in a 2009 sworn statement filed after Cassidy had sought a restraining order against her. The documents were obtained by The San Francisco Chronicle.

The Associated Press generally does not name people who say they have been sexually assaulted.

Cassidy had worked for Valley Transportation Authority since at least 2012, according to the public payroll and pension database Transparent California, first as a mechanic from 2012 to 2014, then as someone who maintained substations.

Officials also were investigating a house fire that broke out shortly before the shooting, Davis said. Public records show Cassidy owned the two-story home where firefighters responded after being notified by a passerby. Law enforcement officers cordoned off the area near the home and went in and out Wednesday.

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Doug Suh, who lives across the street, told The Mercury News in San Jose that Cassidy seemed “strange” and that he never saw anyone visit.

“I’d say hello, and he’d just look at me without saying anything,” Suh said. Once, Cassidy yelled at him to stay away as he was backing up his car. “After that, I never talked to him again.”

Wednesday’s attack was the deadliest shooting in the San Francisco Bay Area since 1993, when a gunman attacked law offices in San Francisco’s Financial District, killing eight people before taking his own life.

It also was Santa Clara County’s second mass shooting in less than two years. A gunman killed three people and then himself at a popular garlic festival in Gilroy in July 2019.