The death toll rose late Wednesday night from the morning shooting at a San Jose, California light rail yard.
Authorities initially said an employee killed eight co-workers and wounded several others when he opened fire, but later said a ninth victim had succumbed to his wounds after being hospitalized in critical condition.
Officials said the suspect, 57-year-old Sam Cassidy, shot himself to death as officers closed in.
Investigators are trying to determine his motive.
There have been more than 60 mass shootings in the U.S. this month alone.
President Biden called the shooting a “horrific tragedy” and ordered that flags be flown at half- staff to honor the victims. In a statement, he said “enough” and urged Congress to take immediate action on gun control legislation.
At the scene, a visibly shaken Governor Gavin Newsom lauded the heroism of the first responders and addressed the difficulty in dealing with yet another mass shooting.
“There’s a sameness to this,” he said, “and I think that numbness is something we’re all feeling. … It begs the damn question, what the hell is going on in the United States of America? What the hell is wrong with us? And when are we going to come to grips with this?”
Cassidy had worked for the Santa Clara Valley Transportation Authority since at least 2012.
His ex-wife, Cecilia Nelms, told CBS News “his temper … was one of our biggest problems.”
Still, she said, she was “just in shock, because I never thought he would do anything like that.”
Workers and family members waited across the street as law enforcement combed the facility.
The victims ranged in age from 29 to 63.
Bagga Singh’s cousin, Taptejdeep Singh, was one of them.
“We heard that (the gunman) chose the people to shoot, but I don’t know why they choose him because he has nothing to do with him,” Singh told CBS News.
Police and Santa Clara County sheriff’s deputies got multiple 911 calls at about 6:30 a.m. The rail yard is next door to the Sheriff’s Office and a block from the San Jose Civic Center and county offices, CBS San Francisco says.
Authorities said about 75-80 people were at the facility when the shooting started, right around when the shift change for VTA workers was scheduled.
The investigation was complicated after a bomb-sniffing dog detected possible explosives at the site. Authorities spent the entire day combing through the facility to make sure there weren’t any explosive devices on the premises.
The VTA shut down rail service at noon as the search by the bomb squad continued. Officials said they didn’t know when rail service would be restored. Buses ran through the day.
“These folks were heroes during COVID-19. The buses never stopped running, VTA didn’t stop running. They just kept at work, and now we’re really calling on them to be heroes a second time to survive such a terrible, terrible tragedy,” said Santa Clara County Supervisor Cindy Chavez.
Cassidy is listed as the owner of a home 13 miles away that caught fire around the time of the shooting.
Fire crews got the fire under control within a few hours. Officials say cans of gasoline and hundreds of rounds of ammunition were found inside the home. Authorities described some of the items as “bomb-making materials.”
San Jose Mayor Sam Liccardo announced there would be a vigil for the shooting victims at 6 p.m. Thursday at City Hall Plaza.