SAN JOSE (KRON/AP) – A gunman who killed nine co-workers at a San Jose VTA rail yard last month was the subject of four investigations into his workplace conduct, and after one verbal altercation a colleague worried that the man could “go postal,” according to internal documents published Thursday.

While Cassidy received no formal discipline for threatening behavior of violence during his 20-year career at VTA, there were four separate incidents involving Cassidy that were elevated to management.

These resulted in disciplinary actions that ranged from a verbal warning to a two-day leave without pay. 

It was the first time the rail authority has said whether there were warning signs or if co-workers ever raised concerns about Cassidy before he opened fire on colleagues at the rail yard.

  • July 16, 2019: Insubordination. Cassidy was sent home without pay for two days, as a result of refusing to follow company policy in signing out a two-way radio that was necessary to perform his job.
  • January 29, 2020: A verbal altercation between Cassidy and a coworker was reported to VTA Employee Relations and the VTA Office of Civil Rights. Upon questioning from a supervisor, a coworker reported that another unnamed employee stated of Cassidy “He scares me. If someone was to go postal, it’d be him.”  The individual refused to name the source of that comment. Upon further investigation, there was nothing in Cassidy’s disciplinary history, or additional information to explain or support that concern. The matter was referred back to Cassidy’s department manager. VTA is continuing to research this incident to see if there is any other relevant documentation to review and release.
  • October 21, 2020: Cassidy refused to attend a mandatory CPR recertification class citing his concern about the threat of COVID. A number of reasonable accommodations were provided to the employee with no ultimate resolution.
  • November 28, 2020. Unexcused leave and improper radio communication. After having trouble clocking in for a work shift, Cassidy inappropriately used a VTA two-way radio for personal communication, rather than for operational matters, which is against VTA policy. He left work without permission instead of resolving the problem.

“Upon further investigation, there was nothing in Cassidy’s disciplinary history, or additional information to explain or support that concern,” the authority wrote in a statement Thursday.

In the two weeks since the shooting, questions have swirled about what might have set off Cassidy’s lethal rampage and whether there were warning signs.

Authorities have described him as a “highly disgruntled” employee at the Valley Transportation Authority, where he had worked for more than 20 years.

His ex-wife said after the shooting that he had expressed hatred and resentment of his workplace for at least a decade. A co-worker described him as an outsider who didn’t mingle with others.

Neighbors and former lovers described Cassidy as moody, unfriendly and prone to angry outbursts at times, especially after drinking. But they expressed shock he would kill.

After the mass shooting, authorities found an arsenal and 25,000 rounds of ammunition at Cassidy’s home, which he tried to burn down before going on the deadly shooting spree. Santa Clara County sheriff’s officials said they found weaponry that included 12 guns, nearly two dozen cans of gasoline and a dozen or more suspected Molotov cocktails.

The Associated Press contributed to this report.