Police beat a woman in a Sydney street. Their own camera captured their cruelty

An officer kicks Jodi Knott, in body-worn camera vision her family has fought to have released. (Supplied)

The shaky video on the laptop shows a naked woman crouching under a tree by a Western Sydney street, experiencing a psychotic episode.

Plain-clothes NSW police officer Senior Constable Nathan Black puts on blue surgical gloves.

"It is about being scared of you," she screams. "I'm terrified of you people. Go away."

So begins one of the most brutal and calculated police assaults ever filmed in Australia.

Warning: This story contains confronting descriptions of violence and coarse language

The woman's cousins, Nichole Allen and Sharee Castagna, wrap their arms around each other as they stare at the laptop. It's the first time they've seen the footage.

Nichole and Sharee watch the footage of the attack. (Four Corners)

They want the public to see what was done to their loved one, and to know her name: Jodi Knott.

Jodi died of cancer 18 months after the callous 2023 attack. Her relatives want her legacy to be better police training in responding to acute mental illness.

"You can't physically beat me. F*** off," Jodi, who lived with schizophrenia, yells in the video.

Jodi turns and runs onto the road. Black chases her and they tumble to the ground.

What happens over the next hour was later described as "gratuitous cruelty" by a District Court judge.

Black and his partner Constable Timothy Trautsch stomp on Jodi as she lays on the road. Black kicks her in the head, and at one point drags her by the hair along the bitumen, leaving her back red and raw. He later points his can of pepper spray directly at grazes on her body and sprays them.

Jodi is also sprayed at close range in the face, something that is forbidden because of the risk of eye injuries.

"Get it in her eyes, get it in her eyes," one officer can be heard saying in footage, recorded by Black's police-issued body-worn camera.

By the end, both men have emptied their pepper spray canisters.

"God, please. I'm strong God, but not without you," Jodi yells in fear.

Jodi's cousins stop the video. They walk outside to get some air.

Jodi's cousins take a break after watching the video. (Four Corners)

"They didn't care that there were cameras around or that their body-cam footage was on," Sharee says.

"That says to me that there is a significant cultural issue within the police … that this type of behaviour is OK."

"She had nothing on her," says Nichole. "She was naked. She's vulnerable.

"What is she going to do to them? Two burly blokes rocking up like that. She's not going to do anyt