(SAN JOSE, Calif.) -- The suspect in a mass shooting that killed nine at a San Jose, California, light rail yard was found dead with two semiautomatic handguns and 11 magazines with ammunition nearby, officials said Thursday.
The guns are believed to be legally purchased and didn't appear to be modified, Santa Clara County Sheriff Laurie Smith said Thursday.
Everyone who was shot Wednesday morning died.
Authorities do not have a motive for why Samuel Cassidy, a Santa Clara Valley Transportation Authority employee, allegedly gunned down nine men at the VTA light rail yard. The suspect died from an apparent self-inflicted gunshot wound.
VTA worker Kirk Bertolet told ABC News that Cassidy was a loner who was "never a part of the group."
Bertolet was in a secure room at the transit hub when shots rang out. He said he felt helpless listening to the gunshots. When the shooter moved to another building, Bertolet said he ran to help his friends and coworkers -- but they were already dead.
Bertolet said he believes the shooter targeted his victims and spared others. He said the gunman looked at one of his coworkers, who was curled up on the floor, but didn't shoot her.
"She was right among everybody else," he said.
After the shooting, a police dog detected a suspicious device and a bomb squad began working to clear each room in the facility, authorities said.
The explosive materials have since been traced to the suspect’s locker where Smith said authorities found precursor items to building explosives but no actual devices. Similar explosive materials were also found at his home, Smith said Thursday.
A house fire reported minutes after the shooting is also believed to be linked to the suspect.
Given the timeline of 911 calls -- an active shooter was reported at 6:34 a.m. and the fire reported at 6:37 a.m. -- Smith said authorities believe the suspect had a device set to ignite the fire. Smith said there's no information to connect another suspect to the fire.