It shows Gaurav Kundi, 42, who is now on life support, being forced onto Payneham Road in the city’s eastern suburbs, as he and his partner scream that he’d done nothing wrong.

The father-of-two lost consciousness.

He can be seen being tackled to the ground, with his partner filming and yelling what police were doing was “unfair.”

Amritpal Kaur said she stopped filming as one of the officers drove their knee into her partner’s neck.

“Just 19 seconds video because I got panicked and I just sit on the ground with Gaurav,” she told 9News.

Another video shows Kundi unresponsive.

“I was keep saying he’s not well, he’s not well please don’t do this, just call the ambulance,” Kaur said.

Kundi was taken to the Royal Adelaide Hospital where he remains in a critical condition.

“Doctors are saying his brain is totally damaged. Maybe he will wake up if brain works, or maybe he will not,” Kaur said.

9News has chosen to conceal the identity of the officers involved as an internal investigation looks at exactly what unfolded in the early hours of Thursday morning.

Kundi had been drinking before he left his Payneham home and began walking along Payneham Road.

Footage shows him on the ground as his partner approaches.

“I just go out and follow him. What are you doing here? Let’s get back home. You are drunk. You are not well. We will go home,” she said she told him.

“He just pushed me a little bit. You get aside, I can walk.”

Kaur believes it may have been that shove that caught the attention of a passing patrol.

“The policeman think he’s assaulting me and doing domestic violence on the road but policeman is wrong,” she said.

“He is just drunk and that’s why he is loud, nothing else.”

Police said their suspect violently resisted officers.

9News does not have footage of the moment the man became unresponsive.

But his partner alleges he was injured when his head was slammed into the police car and the road and that while he was on the ground he was kneed in the neck.

“His brain is damaged because policeman hit very badly on the road. On the car, his head. And his neck nerve,”  Kaur said.

She said she tried to warn them about pre-existing health conditions.

“His health is not very good and is heart is not working,” she said.

On Friday, South Australia Police said it was so far satisfied officers acted appropriately.

“I can say that from that evidence I’ve looked at, from that body-worn video, but it is only one portion, I’m comfortable, but that is only one police officer,” Acting Assistant Commissioner John DeCandia said.

Premier Peter Malinauskas said he and the police minister were backing in the police at every opportunity.

After seeing the video, 9News asked more questions including whether both officers had their body-worn cameras switched on.

Police said they had nothing further to add.

Kaur said her partner was on life support.

“I am just sitting over there and praying to God. Nothing else I can do. Nothing else I can do,” she said.