San Jose mass shooting: Dramatic bodycam footage shows officers responding to carnage

Newly released body camera video shows the dramatic moments deputies responded to the mass shooting at the VTA light rail yard in San Jose, California.

The video and timeline, released by the Santa Clara County Sheriff's Office on Tuesday, shows first responders reaching the scene where nine VTA employees were gunned down.

The first call reporting the May 26 massacre was received at 6:34 a.m. and deputies were dispatched 40 seconds later, officials said.

Body camera video showed a VTA worker giving officers his badge so they could enter one of the buildings. The worker told officers the suspect was armed with a handgun and last seen in building A, authorities said.

The first responders -- two sheriff’s deputies and three San Jose police officers -- were seen entering the dark VTA dispatch center and moving through the rooms to try to clear them. Gunshots were heard as the officers approached the dispatch center's exit doors and a bullet hole was visible in the window frame of a door.

As the officers approached a door, they spotted a person down on the other side. They burst through the door, shouting, "Let me see your hands!"

The person down later was determined to be the suspect, employee Samuel Cassidy, officials said. Cassidy died from two self-inflicted gunshots.

Once the suspect was secure, officers continued searching for victims, officials said.

"We'll never forget those innocent victims whose lives were taken by a crazed coward," Santa Clara County Sheriff Laurie Smith said at a Tuesday news conference.

Cassidy, described by his co-workers as "disgruntled," planned the massacre and "was prepared to use his firearms to take as many lives as he possibly could," the sheriff's office said last week.

At Cassidy's home, investigators found multiple cans of gasoline, suspected Molotov cocktails, 12 guns and about 22,000 rounds of various types of ammunition.

The processing of the large crime scene at VTA concluded Sunday night, officials said.

ABC News' Abigail Shalawylo contributed to this report.