SAN JOSE (CBS SF) – In radio traffic recordings just released by the Valley Transportation Authority, confusion and then warnings to hide from the gunman can be heard among rail controllers, train operators and employees with radios during last month’s mass shooting in San Jose.

“What we have right now is shots fired, make sure your doors are closed,” an employee says to a train operator in the beginning of the released recordings.

“Michelle, we have, we have shots fired in building B at Guadalupe,” someone tells the VTA’s communication center.

“There’s something going on.”

“Getting yells from building B to call the police.”

“All trains, all trains in the yard hold your 10-20. Once again, all trains, all trains hold your 10-20.”

“Yeah honey, what’s going on,” one woman asks someone.

“Uh, secure … whoever’s with you … secure the doors,” a man replies.

At the time, the employees had no idea Samuel Cassidy was committing what would be the Bay Area’s deadliest mass shooting.

The long-time VTA employee had been investigated by the agency in the past for insubordination, and a verbal altercation with a coworker, according to personnel files released by the VTA earlier this month. One colleague, the personnel files said, stated to another co-worker that “he scares me. If someone was to go postal, it’d be him.”

In 2016, U.S. Customs and Border Protection detained Cassidy after a trip to the Philippines and reportedly discovered he was in possession of “books about terrorism and fear and manifestos…as well as a black book filled with lots of notes about how he hates the VTA.”

The federal agents never informed local authorities about what they discovered or that they had even interviewed Cassidy.

District Attorney Jeff Rosen has vowed to figure out why Cassidy fell through the cracks.

“How many shots were fired,” an employee is heard in the newly released audio recordings.

“At least 10 or 15, and people were screaming over there,” someone replies.

“Where you at, you need to shelter in place, hide, go inside, whatever you need to do,” a male warns a co-worker.

In another clip a woman tells the communication center she is hiding from the gunman.

“I’ve locked up, we’ve shut our room down,” she says.

“OK good. Just stay inside,” a male replies.

“We’re going to stay inside, and if something happens we’re going to bring everybody in my room and lock them up,” the woman says.

The audio recording then picks up several gunshots before someone is heard saying, “Someone’s shooting right outside the door upstairs.”

Law enforcement from the Santa Clara County Sheriff’s and San Jose Police Departments entered the VTA building about five minutes after Cassidy opened fire.

Body camera footage released by the sheriff’s office earlier this month shows a team of law enforcement officers entering the building and running toward gunshots before they discover Cassidy’s body. He had turned the gun on himself in an office, but not before taking the lives of nine of his colleagues — some of them who died while protecting their co-workers.

“You guys OK,” someone is heard saying toward the end of the audio files while sirens can be heard in the background.

“Whoever it is, is on the third floor.”

“OK, I’ll let ’em know.”

“We got one down in the B building.”