The suspected gunman in the shooting at a San Jose, California, light rail yard has been identified as Sam Cassidy, a law enforcement source with knowledge of the investigation confirmed to CNN. Cassidy did not exchange gunfire with officers who responded to the shooting, according to police, and it has been initially determined he died by suicide.Authorities have yet to establish a motive for the shooting. Here is what we know about Cassidy:Read MoreHe was an employeeCassidy was an employee at the Valley Transportation Authority (VTA), said San Jose Mayor Sam Liccardo. The VTA is a public transit service that operates bus and light rail services in the Santa Clara Valley and employs about 2,000 workers.”It’s clear the victims and all the colleagues knew the shooter well,” Liccardo told CNN’s Jake Tapper on Wednesday. A 9th victim of the San Jose mass shooting has died. Now investigators are focused on why it happenedThe victims, VTA employees, were working at a light rail maintenance facility. Santa Clara County Sheriff Laurie Smith said the victims worked together and were there in the morning together. Liccardo described them as “essential workers” who risked their lives and showed up every day throughout the pandemic.It has not yet been determined whether those shot and killed were targeted. The women in his life said he had anger issuesCassidy had a strained relationship with an ex-girlfriend, court documents show, which revealed troubling allegations she made in a filing in 2009 as she responded to a restraining order he filed against her.The woman says she dated Cassidy for approximately one year in what she said became an off-and-on-again relationship after about six months.She described Cassidy as having mood swings that were “exacerbated when (Cassidy) consumed large quantities of alcohol,” she said in the court document, and she alleged he had bipolar disorder.She said he enjoyed playing mind games with her, according to the court document.”Several times during the relationship he became intoxicated, enraged and forced himself on me sexually,” said the former girlfriend, who CNN is not naming and is reaching out to for comment.The pandemic's essential workers are again the victims of a mass shooting — this time in San JoseCassidy’s ex-wife, Cecilia Nelms, told CNN affiliate the Bay Area News Group he resented his work. Nelms was married to Cassidy for about 10 years until the couple filed for divorce in 2005. She has not been in touch with her ex-husband for about 13 years, according to the outlet.”He had two sides,” Nelms said. “When he was in a good mood he was a great guy. When he was mad, he was mad.”He often spoke angrily about his co-workers and bosses, and at times directed his anger at her, Nelms told the outlet.When the two were married, he “resented what he saw as unfair work assignments” and “would rant about his job when he got home,” she said.”He just thought that some people got more easy-going things at work, and he’d get the harder jobs,” she said.Emergency responders leave a home, rear, being investigated in connection to a shooting in San Jose, California.He was described by a neighbor as ‘strange’Surveillance video obtained by CNN shows a man identified as Cassidy leaving his home on Wednesday morning with a duffle bag.A neighbor, who did not want to be named, said the video was captured around 5:40 a.m. and showed Cassidy leaving the house in a truck. The neighbor described Cassidy as a “quiet” and “strange” man.The neighbor later noticed a fire broke out at Cassidy’s home around 6:30 a.m.Firefighters responded at a home in the 1100 block of Angmar Court in San Jose at 6:36 a.m. local time, according to tweets from the San Jose Fire Department. The time was just minutes after police were called about the shooting at the VTA facility, about 8 miles away.Liccardo said in an interview with CNN affiliate KGO that a fire was reported at the home of the gunman. No one was found inside the home, he said.It took firefighters about an hour to extinguish the two-alarm fire, which caused heavy damage and left the structure uninhabitable, the fire department said.