WATCH: Video catches fatal moment when officer shoots & kills woman instead of dog [UPDATE]

Newly released body camera footage reveals the fleeting and frantic moments when a Texas police officer fatally shot a woman on Thursday after a dog ran toward him, the Dallas Morning News reports.

On Friday, authorities in Arlington, Texas, disclosed the footage, which shows the officer firing shots just a few seconds after the dog started running after him.

The unidentified officer instead hit Margarita “Maggie” Victoria Brooks, 30, who was reportedly passed out on the ground near the dog. She was shot once in the chest and was declared dead at 6 p.m. at a local hospital.

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The officer had responded to a call for a welfare check on Brooks around 5:15 p.m. As he approached the woman, the dog started running toward him and barking. The officer then distanced himself from the dog, took out his gun and fired three shots.

Brooks is heard in the video yelling after he fired the shots when it was evident the woman had been hit.

Arlington Police Chief Will Johnson said during a news conference that the officer had been trained on how to use his gun and deal with dogs.

“Everything about this call is an absolute tragedy,” Johnson told reporters. “Our hearts are broken for the Brooks family and the police officer involved.”

It was not clear whether Brooks owned the dog, which was taken to an animal shelter. A bullet may have grazed the dog, described as a 40-pound Labrador retriever mix.

The police officer is 25 years old. Although he has worked for the department for seven years, much of that time was as a detention officer; he graduated in February from the police academy and did not begin fieldwork until July 1.

The officer has since been put on administrative leave, which is standard in police shootings.

Investigators are conducting both a criminal inquiry and an administrative probe to assess whether the officer followed departmental policy.

The bodycam footage shows the officer asking Brooks “Are you OK? Is that your dog?” while he walks on a sidewalk.

The dog then begins running toward him and barks, prompting the officer to shout “get back!”

Within two seconds, the officer fired three shots toward the dog as he was moving backward. The dog then turns around and runs toward Brooks, who can be heard in the video screaming “what the [expletive]! Oh my god. Police shot me.”

The officer uses his radio to report shots fired and then tells Brooks to “get a hold of your dog.”

People familiar with Brooks described her as homeless and a fixture in the neighborhood. A nearby resident said the dog was well cared for.

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[Feature Photo: Maggie Brooks/Facebook]