The Santa Clara County Sheriff's Office has released body-worn camera footage from the department's response to the mass shooting at the VTA maintenance yard last Wednesday — which happened relatively quickly after the shooting began, because the Sheriff's Office San Jose headquarters is next door to this rail yard.

The shooting was said to have begun at a union meeting during a shift change around 6:30 a.m. on May 26. 57-year-old Samuel Cassidy, a disgruntled VTA employee, brought multiple high-capacity magazines and semi-automatic handguns to the workplace and began targeting specific coworkers, ultimately murdering nine of them.

"We’ll never forget those innocent victims whose lives were taken by a crazed coward,” said Sheriff Laurie Smith during a press conference Tuesday at which the body cam footage was released, per San Jose Spotlight.

Smith added, "There were over 100 VTA employees on site that morning and I believe the bravery of all of law enforcement personnel really prevented the loss of additional life."

The footage begins after Cassidy had reportedly crossed the maintenance yard to a second building, to a control center on the third floor, where arriving officers were told they would find him. The arriving group included several San Jose Police Department officers as well.

Gunshots can be heard as they cautiously approach the building, climb an exterior staircase, and enter the workplace — which they did with the help of a VTA employee who exited one of the doors and loaned them his key card.

Inside, the officers walk through a deserted office space and don't appear to see any victims. They then hear at least one shot inside an adjacent hallway or stairwell, which appears to have been aimed toward them, to a glass window in the top of one of the doors they entered through. Once inside, there are two more shots, and they find Cassidy just as he takes his own life, slumped in a chair.

WARNING: The footage is somewhat graphic in nature, though parts of the video have been blurred.

As Smith explained, "We believe that shot that went through the window casing was the first of three shots, but that’s preliminary right now because the crime scene people are not totally done. He shot himself once under the chin. It wasn’t fatal and then in the side of the head."

Smith also said that law enforcement changed tactics in mass shooting situations after the Columbine High School shooting in 1999, and they no longer wait before SWAT forces arrive.

"We immediately go in, even if it’s just one deputy — we’ll go in,” Smith said. "In this case, we had five on the first contact team. I thought it was important to show that this protocol, I believe, saved lives. There were more than 100 people in that area and he had lots of additional ammunition and had most likely set the fire at his house before."

The reason Cassidy took a shot toward the doorway was likely because he saw the officers' gun flashlights in the window as they arrived, Smith said, so he took his own life knowing that the officers were there.

"I would believe he either heard us or saw the flashlights through the windows he had apparently shot through," she said.

The investigation is ongoing and an explicit motive may never be known. However, coworkers and Cassidy's ex-wife gave statements to the press last week suggesting that Cassidy had been angry toward coworkers and the VTA for over a decade, and had been somewhat of an outsider in the workplace.

A report last week that Cassidy was facing a disciplinary hearing of some kind due to racist remarks in the workplace has since been denied by the VTA and Cassidy's union president.

Related: San Jose Gunman Was Allegedly Being Disciplined For Racist Remarks In Workplace