Prosecutors say shooting that left two African Americans dead in the US state is being probed as possible hate crime.

Moments after allegedly killing two African Americans at a supermarket in the US state of Kentucky, 51-year-old Gregory Bush reportedly muttered to a white bystander, “Whites don’t kill whites.”

Bush, who is white, has been charged with two counts of murder and 10 counts of wanton endangerment, and a judge set his bail at $5m on Thursday.

A federal prosecutor said on Friday that the shooting is being investigated as a possible hate crime.

US Attorney Russell Coleman said federal investigators are investigating whether there were any violations of federal law, “which includes potential civil rights violations such as hate crimes”. The FBI is investigating alongside local police.

Before entering the Kroger supermarket in a suburb of Louisville, Kentucky, on Wednesday, Bush attempted to break into a nearby predominantly African American church, police said.

After failing to enter the church, Bush entered the supermarket and shot dead 69-year-old Maurice Stallard, according to police, before killing 67-year-old Vickie Jones in the car park.

Local media reported that Stallard’s 12-year-old grandson witnessed his killing.

An armed bystander exchanged gunfire with the suspect in the car park of the Jeffersontown store before the shooter fled in a car. He was taken into custody soon afterwards, Jeffersontown Police Chief Sam Rogers said at a news briefing outside the store. There were no further injuries, he said.

“It does appear she was a random victim out in the parking lot,” said Rogers. Asked if the male victim in the store was also killed at random, Rogers said. “It does appear to be possibly the case.”

{articleGUID}

Steve Zinninger told Wave3 News that his father was waiting outside the supermarket while his mother shopped inside when he heard shooting and saw panicked people running from the store.

‘Please don’t shoot’

Zinninger said the shooter casually walked towards his father in the car park and his father drew his gun and confronted the man from behind his car.

“He [the armed man] said, ‘please don’t shoot and I won’t shoot you,’ whites don’t kill whites,” Zinninger told Wave3 News.

It was not clear whether Zinninger’s father was the armed bystander who Rogers said exchanged gunfire with the suspect.

Video taken by a store owner showed the suspect wandering around the car park as bystanders shouted his location to police. The man then sped off, chased by a police officer on foot.

“Thanks to the quick response of the local police department, the suspect was apprehended and our store is secure,” Kroger said in a statement.

Drew Butler said he was shopping in the store when he heard multiple shots. He and a woman barricaded themselves inside a room.

“After the fourth shot, I don’t know if there were five or 15,” Butler told Wave3 news.

Rogers said both the man and woman were shot multiple times.

Local media reported that Bush had a long history of criminal offences, including assault and domestic violence.