A jury is deciding whether a former detective showed “extreme indifference to human life” during the raid that led to the death of Breonna Taylor.
Brett Hankinson allegedly fired 10 shots blindly into a neighbour’s flat in the melee that followed a “no-knock” search of the black woman’s Kentucky home.
He is now standing trial on three charges of endangerment.
Ms Taylor’s death sparked racial injustice rallies across America.
Officers had forced their way into the 26-year old paramedic’s Louisville home during a narcotics raid using the “no-knock” warrant – which meant they did not have to announce themselves.
Her boyfriend shot and wounded one of the officers. In response, officers fired 32 shots, six of which struck Ms Taylor.
Prosecutors allege that in the raid some of the shots fired by Hankinson entered a neighbouring flat, endangering three people inside: Cody Etherson, his pregnant wife Chelsey Napper and their five-year-old son.
“This is not a case to decide who is responsible for the death of Breonna Taylor,” Kentucky assistant attorney general Barbara Maines Whaley said during her opening remarks on Wednesday, but more whether Hankinson had showed “extreme indifference to human life” during the raid.
But Hankinson’s team sought to portray him as an experienced officer who was facing a confusing situation. Defence attorney Steve Matthews described it as a scene of “total chaos”.
At the trial, Mr Etherson said he believed the raid was “reckless” and described a chaotic scene with bullets shredding through a wall his apartment shared with Ms Taylor’s, covering him in debris and only narrowly missing him and his son.
He said he woke that March night to a “boom”, then heard several shots and felt debris falling on him.
When his glass patio door shattered, Mr Etherton said he went to see what was happening – but was faced with officers pointing guns at him.
The case, in Jefferson County Circuit Court, is expected to take about two weeks.
It is the only trial stemming from the death of Ms Taylor. In 2020, her family sued Louisville police and reached a $12m (£8.8m) settlement.
A grand jury cleared the two white officers who actually shot Taylor but charged Hankison for endangering neighbours in the adjacent apartment.
He has pleaded not guilty but if convicted could face up to fiive years in prison.
Ms Taylor’s death, along with that of George Floyd in Minneapolis, sparked nationwide protests against police brutality and racism against black Americans.