Gregory Bush, has been charged with shooting Maurice Stallard, 69, in front of his grandson in Jeffersontown, some 24 km from downtown Louisville and then shot Vickie Jones, 67.
The shooting of a black man and woman at a Kentucky supermarket was being investigated as a possible hate crime, a federal prosecutor said on Friday.
Gregory Bush, 51, a white man, has been charged with shooting Maurice Stallard, 69, in front of his grandson as they shopped in a Kroger Inc grocery store in Jeffersontown, some 15 miles (24 km) from downtown Louisville. According to an arrest citation, he then went to the parking lot and shot Vickie Jones, 67.
Bush has been charged with murder and 10 counts of first-degree wanton endangerment.
"Federal investigators are supporting local law enforcement and examining this matter from the perspective of federal criminal law, which includes potential civil rights violations such as hate crimes," U.S. Attorney Russell Coleman said in a statement on Friday.
An armed bystander with a carry permit for a concealed weapon exchanged gunfire with Bush in the parking lot before the suspect fled in his car. He was apprehended shortly afterwards, police said.
Ed Harrell told the Louisville Courier Journal that he pulled out his pistol as Bush approached him in the parking lot and Bush told him not to shoot as "whites don`t kill whites."
It was not immediately clear if Bush had legal representation.
If investigators suspect the killings were racially motivated, Bush could also be charged for a hate crime.
Both Stallard and Jones were shot from behind multiple times, Jeffersontown Police Chief Sam Rogers told reporters on Thursday.
Rogers said Bush suffered from mental illness and court records showed he had a history of violence and at least one instance when he used a racial slur.
About 15 minutes before walking into the Kroger supermarket Bush tried to get into a predominantly black Baptist church, police said, citing surveillance video.
First Baptist Church administrator Billy Williams told local CBS affiliate WLKY there were eight to 10 people in the church at the time.
In 2015, self-described white supremacist Dylann Roof, then 21, shot and killed nine black people in a church in Charleston, South Carolina.