A candidate for the metro council in Louisville, Kentucky, has been charged with attempted murder, accused of opening fire on a mayoral candidate whose shirt was grazed by a bullet in his campaign headquarters, police said.

Quintez Brown, 21, also faces four counts of wanton endangerment, Louisville police spokesman Aaron Ellis said.

Police said Brown appears to have acted alone, and the motive remains under investigation.

After a previous incident last year when Brown briefly disappeared, his family said his mental health was among their concerns.

Brown, a social justice activist running as an independent for the council, has campaigned with a slate of candidates opposed to projects they say will worsen gentrification in Kentucky’s largest city.

The apparent target of Monday’s shooting, Democrat Craig Greenberg, has campaigned on his experience at the centre of the city’s revitalisation efforts, and helped draft legislation promoting developments in Louisville’s predominantly black west side.

Craig Greenberg
Craig Greenberg (Timothy D Easley/AP)

He said he was at his campaign headquarters with four colleagues when a man appeared in the doorway and began firing multiple rounds.

“When we greeted him, he pulled out a gun, aimed directly at me and began shooting,” Mr Greenberg said.

“Despite one bullet coming so close that it grazed my sweater and my shirt, no one was physically harmed.”

One staff member managed to shut the door, which they barricaded using tables and desks, and the suspect fled, Mr Greenberg said.

Apprehended a short time later less than half a mile from the scene, Brown was carrying a loaded 9mm magazine in his trouser pocket and had a drawstring bag with a handgun and additional magazines, according to the arrest report.

“Today is not a day for politics, but it’s not lost on me that the violence my staff and I experienced today is far too common in our city. Too many Louisville families have experienced the trauma of gun violence,” Mr Greenberg said on Monday.

Brown, a former intern and editorial columnist for the Courier Journal, has been prolific on social media, tweeting and retweeting comments on social justice issues.

In one recent post, he showed the faces of several young black people killed by gun violence in Louisville, writing: “This is our reality. All of these kids are gone.

“Gun violence reveals the interconnected nature of our reality. What affects one directly, affects all indirectly. Especially in our segregated conditions.”

Mr Greenberg has built a big fundraising lead in a crowded race to succeed outgoing mayor Greg Fischer in the Democratic-leaning city.

A Harvard-educated lawyer, Mr Greenberg helped start Louisville-based 21c Museum Hotels, building the company to more than 1,100 employees.

The company is credited with helping revive Main Street in central Louisville and other urban neighbourhoods across the country.

Brown disappeared for about two weeks last summer. After he was found safe, his parents issued a statement asking for patience and privacy while they attended to “Quintez’s physical, mental and spiritual needs”, the Courier Journal reported.