A former police officer in the US state of Kentucky has been found guilty of violating the civil rights of Breonna Taylor, a black woman killed in her own home during a botched raid four years ago.

Brett Hankison, 47, could face up to life in prison after being convicted of using excessive force against the 26-year-old emergency room technician.

But the jury also found him not guilty on another charge of violating the civil rights of one of Taylor's neighbours. It was the third time Hankison had stood trial in the case.

The verdict marks the first time any officer has been convicted in the deadly raid on 13 March 2020 that made Taylor's name a rallying cry during the racial justice unrest of that year.

Members of Taylor's family in court collapsed in tears after the verdict on Friday, according to the Louisville Courier Journal.

Prosecutors wanted Hankison to be immediately taken into custody, but their request was rejected by the judge, reports the local newspaper.

The jury of five white men, one black man and six white women began their deliberations on Wednesday.

The indictment accused Hankison of depriving Taylor of the right to be free from unreasonable seizures and depriving her neighbours of the right to be free from the deprivation of liberty without due process of law.

He fired 10 times into her apartment, in order, he said, to protect fellow officers as Taylor's boyfriend opened fire when officers broke down the door.

According to the Courier Journal, Taylor's mother, Tamika Palmer, said after the verdict that she began to feel "defeated" as jury deliberations continued, but that she was "glad" the trial was over.

"1,694 days it took. It was long, it was hard, it was — I don't know if I've got some words (other than) 'thank God.'", she said.

Hankison took the stand over two days of testimony during the retrial, telling the jurors he was "trying to stay alive, trying to keep my partners alive".

He was the first of the four officers charged in the case to face a jury.

Another former officer, Kelly Goodlett, pleaded guilty to falsifying the search warrant for Taylor’s home.

The remaining two officers had their federal charges thrown out by a judge earlier this year. The US Justice Department recently indicted the two on new charges.

Taylor was killed after officers wearing plain clothes executed a "no-knock" search warrant at her home. They burst into her apartment in the early morning hours while she and her boyfriend, Kenneth Walker, were asleep.

Authorities believed Taylor's former boyfriend was using her home to hide narcotics.

Mr Walker fired a single shot when they knocked the door down, hitting one officer, Sgt John Mattingly, in the leg. Mr Walker said the officers did not announce themselves as police, and he thought they were intruders.

The three officers returned fire, shooting 32 bullets into the flat.