An employee opened fire Wednesday at a California rail yard, killing eight people before taking his own life as law enforcement rushed in, authorities said, marking the latest attack in a year that has seen a sharp increase in mass killings as the nation emerges from coronavirus restrictions.

The shooting took place around 6:30 a.m. in two buildings at a light rail facility for the Valley Transportation Authority, which provides bus, light rail and other transit services throughout Santa Clara County, the most populated county in the San Francisco Bay Area.

“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. Deputies “were going through hallways saying, ‘Sheriff’s office!’ He knew at that time that his time for firing shots was over.”

The victims, many of them longtime employees of the transit agency, were identified by the Santa Clara County coroner’s office Wednesday night 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.

Their jobs included bus and light rail operators, mechanics, linemen and assistant superintendent. One had worked for the transit authority since 1999.

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.

“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. He said he was told that the gunman targeted certain people and let others go.

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 attacker was identified as 57-year-old Sam Cassidy, according to two law enforcement officials. Investigators offered no immediate word on a possible motive.

His ex-wife, Cecilia Nelms, told The Associated Press that Cassidy had a bad temper and would tell her that he wanted to kill people at work, “but I never believed him, and it never happened. Until now.”

Nelms, teary-eyed and shaken by the news, said her ex-husband would come home wound up and angry about things that happened at work. As he talked about it, “he would get more mad,” she said. “He could dwell on things.”

When Cassidy lost his temper, Nelms said there were times she was scared. He was someone who could physically hurt others, she said.

Nelms said they were married for 10 years — Cassidy filed for divorce in 2005 — and had not been in contact for 13 years. She said he had been treated for depression.

Members of a union representing Valley Transportation Authority workers were meeting when the shooting began, San Jose Mayor Sam Liccardo said, but it’s not clear the meeting was related to the attack.

When she heard shots, transit authority mechanic Rochelle Hawkins said she dropped her phone.

“I was running so fast. I just ran for my life,” she said. “I would hope everyone would just pray for the VTA family. Just pray for us.”

Other friends and family members awaited news after being unable to reach their loved ones through calls or text messages. Some had tracked the missing person’s cellphone to the rail yard but had no information from authorities.

Sheriff’s spokesman Deputy Russell Davis said he did not know the type of weapon used in the attack.

As bomb squads searched the rail complex, officials were also 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 passer-by. Law enforcement officers cordoned off the area near the home and went in and out Wednesday.

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.”

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.

Gov. Gavin Newsom, speaking emotionally in front of a county office where flags flew at half-staff, said victims’ relatives were “waiting to hear from the coroner, waiting to hear from any of us, just desperate to find out if their brother, their son, their dad, their mom is still alive.”

“It begs the damn question, ‘What the hell is going on in the United States of America?’”

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

The bloodshed comes amid a rise in mass killings after the pandemic had closed many public places and kept people confined to their homes last year.

A database compiled by The Associated Press, USA Today and Northeastern University that tracks every mass killing over the last 15 years shows that the San Jose attack is the 15th mass killing so far in 2021, all of them shootings.

Eighty-six people have died in the shootings, compared with 106 for all of 2020. The database defines mass killings as four or more people dead, not including the shooter, meaning the overall toll of gun violence is much higher when adding in smaller incidents.

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.

San Jose, the 10th-largest city in the U.S. with more than a million people, is about 50 miles (80 kilometers) south of San Francisco in the heart of Silicon Valley.

Trains were already out on morning runs when the shooting occurred. Light rail service was suspended and replaced with bus bridges.

Wednesday’s attack 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.

The Gilroy attack was on Mayor Liccardo’s mind Wednesday as text messages flooded in, reporting the shooting and fire.

“Not again,” he thought as he jumped in his car and raced to City Hall. Transit authority workers told him they knew Cassidy.

“You try to understand what would possess someone to do that much harm,” Liccardo said by phone. “It’s unfathomable.”