The gunman who shot nine people in San Jose before killing himself was armed with two handguns, officials said, and may have used a device to set fire to his home remotely.
In an interview with the "Today" show on Thursday morning, Santa Clara County Sheriff Laurie Smith said Samuel Cassidy, 57, was "very deliberate, very fast" during the shooting rampage at the Valley Transit Authority rail yard.
Cassidy had been employed at the VTA for at least eight years.
He was found with two semi-automatic handguns and 11 loaded magazines, Smith said.
Calls about the shooting came in at 6:34 a.m. Wednesday. Three minutes later, a fire was reported at Cassidy's home on Angmar Court, eight miles away.
Officials are operating under the assumption that he acted alone and "set some kind of device to go off at a certain time, probably to coincide with his shooting," Smith said, although she noted that thinking may change as the investigation continues.
Bomb-sniffing dogs at the rail yard also located materials for bombs in what is presumed to be Cassidy's locker, including detonator cords and "the precursors to an explosive," according to Smith.
Authorities are still working to determine whether Cassidy targeted the shooting victims, who were found in two separate buildings at the facility.
Late Wednesday evening, Santa Clara County's office of the medical examiner-coroner identified eight of the victims after notifying next of kin.
They are: Paul Delacruz Megia, 42; Taptejdeep Singh, 36; Adrian Balleza, 29; Jose Dejesus Hernandez III, 35; Timothy Michael Romo, 49; Michael Joseph Rudometkin, 40; Abdolvahab Alaghmandan, 63; and Lars Kepler Lane, 63.
Hours later, officials announced the death of a ninth victim, Alex Ward Fritch, 49, who died Wednesday night at Santa Clara Valley Medical Center after being taken there in critical condition.
Neighbors knew Cassidy as a "very strange, very quiet" guy in his working-class neighborhood, said Ramon Crescini, 64, a retired general contractor who lives several doors down.
Cassidy was divorced more than a decade ago. His ex-wife told the Mercury News that he had a mercurial temper and often complained that co-workers and family members had easier lives than he did.
In April 2009, Cassidy was granted a restraining order he sought against a 45-year-old former girlfriend, whom the Los Angeles Times is not naming as she is the victim of an alleged sexual assault.
Speaking at a news briefing Wednesday, Gov. Gavin Newsom said there is a "sameness and a numbness to these incidents" after meeting with family members of the victims. He asked when the violence will stop.
"What the hell's going on in the United States of America?" Newsom asked. "What the hell's wrong with us? … When are we going to put down our arms, literally and figuratively?"
Speaking to the "Today" show, Smith expressed similar disbelief.
"What in the world could possibly prompt someone to take this kind of action, we don't know at this point," she said.
