SAN JOSE, Calif. (KGO) -- The Santa Clara County Sheriff's Office has released new surveillance video showing the moment after an employee gunned down several people at a San Jose railyard.
The video shows the suspect walking away from a building where he shot multiple coworkers and towards another area where he would kill more victims, according to authorities.
On Thursday law enforcement agencies announced the suspect had a long history of dissatisfaction with his employer.
He was once stopped by Customs and Border Protection while returning from the Philippines in 2016, sources tell ABC News. He was stopped and searched because he was carrying books about terrorism and manifestos, according to three sources familiar with the investigation. CBP found he was also carrying a notebook that detailed hatred of his workplace, the Valley Transportation Authority.
The man appears to have targeted some of his victims, according to the Santa Clara Sheriff's Department.
"We can say that the suspect has been a highly disgruntled VTA employee for many years, which may have contributed to why he targeted VTA employees," the sheriff's department said in a statement.
A witness who survived the shooting told ABC7 News that from his vantage point, it looked like the gunman didn't fire indiscriminately. Rather, he let some people live and chose to kill others.
The shooter had talked about killing people at work more than a decade ago, his ex-wife said.
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"I never believed him, and it never happened. Until now," a tearful Cecilia Nelms told The Associated Press Wednesday following the 6:30 a.m. attack at a lightrail facility for the VTA.
"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 gunman had three semiautomatic handguns and 32 high capacity magazines, according to the sheriff. He fired 39 rounds inside. A locker at the rail yard believed to be the gunman's contained "materials for bombs, detonator cords, the precursors to an explosive," Smith said.
The number of people fatally shot by the gunman rose from eight after the Santa Clara County's medical examiner-coroner late Wednesday confirmed the death of Alex Ward Fritch, 49. He had been wounded and hospitalized in critical condition after the attack.
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Officials have identified all of the victims. Among them is a 36-year-old father of two and a longtime friend of a San Jose councilmember.
No one else was injured in the massacre at the rail yard and all of the victims who were shot have died, Sheriff Smith said.
The suspect has been identified as 57-year-old VTA employee Samuel J. Cassidy. He reportedly set fire to his home on Angmar Court before the shooting. When firefighters arrived on scene, no one was inside the home.
"It would appear as if the fire was set as the shooter was on his way to the work site," said San Jose Mayor Sam Liccardo.
Video obtained by ABC7 News from one of the shooter's neighbors shows a huge plume of smoke rising from the house and firefighters arrive on scene. The video was taken about the same time the shooting began at the rail yard.
The first calls from the VTA facility came in at 6:34 a.m. The shooting was in the area of 100 W. Younger Avenue at a VTA control center and rail yard, where light rail cars are stored. The building is not open to the public, so the shooter would have needed employee access or to have broken in, said VTA spokesperson Brandi Childress.
At the time of the shooting, there was a union meeting going on with about 80 people in attendance.
When law enforcement arrived on scene, multiple people had been shot in two separate buildings, the sheriff's office said, and the shooting was ongoing. About 40 people were rescued from inside by multiple law enforcement agencies who responded to the scene.
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The sheriff's office told ABC7 News Thursday that VTA employees at this location had been through active shooter training within the last year.
Deputies didn't fire their weapons, Davis said, leading them to believe the gunman died from a self-inflicted gunshot wound.
During their investigation, bomb sniffing dogs flagged officers to potential explosives, prompting them to clear the building. Law enforcement expects to be on scene through the night thoroughly searching the building. Bomb squad technicians were also searching the suspect's home for explosives Wednesday. Ammunition and cannisters were found at the suspect's home and sources tell ABC News he had multiple weapons.
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"This is every mayor's worst nightmare," said Mayor Liccardo.
Gov. Gavin Newsom, who arrived in San Jose Wednesday afternoon called the tragedy part of a "pandemic of gun violence."
"There's a numbness I imagine some of us are feeling about this because there's a sameness," Newsom said. "It feels like this happens over and over and over again. Rinse and repeat, rinse and repeat."
He urged leaders to "wake up to this reality and take a little damn responsibility" and to "move beyond the platitudes and usual rhetoric."
Concerned and distraught family members started to gather at the reunification site as word got out. Several people told ABC7 News they weren't able to reach loved ones by phone. One person was trying to use Apple's "Find My iPhone" feature to track down a family member. They saw the iPhone was on and in the building, but wasn't moving.
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Starting at noon Wednesday, VTA suspended all light rail service indefinitely. The agency added bus bridges to ensure continued service.
"The light rail yard remains an active investigation scene, limiting our ability to provide service," the agency tweeted.
A fund has been set up to support victims' families. For information on how to donate, click here.
A vigil is planned for 6 p.m. Thursday at City Hall Plaza in San Jose.
Take a look at the latest stories and videos about the mass shooting at the VTA rail yard in San Jose.
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The Associated Press contributed to this report.