The demonstrators were marching to Churchill Downs on Saturday to demand justice for Breonna Taylor, who was shot dead by local police in a botched up drug raid last year.
The diner was eating at upscale French restaurant La Chasse when he confronted at least 50 BLM protestors and pulled out a gun.
Alicia Smiley, the local police spokesperson told the media that “multiple armed protesters entered the restaurant property, which included outdoor dining space.”
The footage captured by a local reporter of the gun-wielding diner soon went viral on social media.
In the video, a man is seen pointing his pistol at several protesters. Several protestors also appeared to be carrying firearms. It is legal to carry handguns in Kentucky.
A female demonstrator was also seen in the footage asking others to move away down the block.
Ms Smiley said: “During the encounter both patrons and protesters brandished firearms.
“This incident occurred after the arrests of southbound protesters in the area on the 1500 block of Bardstown Road. The arrests of that group were made after protesters repeatedly blocked the roadway despite officers giving multiple verbal requests for them to utilise the sidewalk.”
The Louisville Metro Police department said at least five people were arrested in connection with the incident.
“Charges include possession of a handgun by a convicted felon, failure to disperse and evading police,” TMZ reported.
It was unclear from local reports whether the man who had brandished the pistol at BLM protesters had been arrested or not.
Protesters carried signs reading: “We haven’t forgotten Breonna”, “No Justice, No Peace” and “No Justice, No Derby,” the Louisville Courier-Journal reported.
Black Lives Matter Louisville, Black Market KY, Colour of Change and UltraViolet also commissioned a plane banner that flew over Churchill Downs with the message: “Protect Black Women. Divest from Police.”
It came weeks after the U.S. Attorney General Merrick Garland announced that the Justice Department would be conducting an investigation into the Louisville-Jefferson County Metro Government and the Louisville Police Department more than one year after Breonna Taylor was fatally shot by a city police officer conducting a search warrant at her apartment.