A mass shooting at a Baton Rouge, La., nightclub early Sunday injured a dozen people, leaving one of them in critical condition, in what authorities say was a “targeted attack,” the police said.

“This was not a random act of violence, based on the preliminary investigating efforts. We believe that this was a targeted event, where someone was specifically targeted and others were injured in that process,” Baton Rouge Police Chief Murphy Paul said, according to the Associated Press.

Three police officers heard the gunfire at the Dior Bar & Lounge around 1:30 a.m. and responded immediately, Paul stated at a news conference Sunday afternoon. He credited their quick action, including administering first aid, for preventing further injuries.

No arrests were made in the ongoing investigation, Paul stated. The police have some leads but asked for the public’s assistance, urging people who know something to “do the right thing.”

Baton Rouge Mayor Sharon Weston Broome called the shooting “a senseless act of violence” in a Twitter post, vowing that it “will not go unchecked.”

This mass shooting, the sixth over three years, is part of a trend of increasing homicides in Baton Rouge, according to local newspaper The Advocate. A shooting at an off-campus fraternity house party near Southern University left nine people injured.

WBRZ reported in November that local leaders and U.S. Attorney Ronald Gathe held a press conference Nov. 30 to share their plan to reduce gun violence in East Baton Rouge, as the police tried to solve a growing list of killings. Authorities confiscated more than 1,700 guns and made arrests in 63 homicides at that point last year.

“We will not stop our work until everyone feels safe and individuals no longer turn to guns to resolve their differences,” Broome tweeted. “Please join me in praying for the victims and their families.”