SACRAMENTO, Calif (AP) - At least two shooters opened fire early Sunday in Sacramento in the city’s second mass shooting in five weeks, killing six people and wounding 12 others as bars closed for the night and crowds emptied onto downtown streets, police said.

Three men and three women were killed, Police Chief Kathy Lester said. Their bodies remained on the pavement hours after the gunfire erupted around 2 a.m. Police sought clues from a crime scene that stretched across multiple city blocks as they searched for the shooters.

At least four of the wounded were hospitalized with life-threatening injuries. Authorities have not offered a possible motive and have so far identified only one victim, 38-year-old Sergio Harris, without providing a cause of death.

His sister Kay Harris, 32, told The Associated Press just hours after the shooting that she had been asleep when a family member called to say they thought her brother had been killed. She said she thought Sergio Harris had been at the London nightclub, which is near the shooting.

Investigators pored through hundreds of pieces of evidence - much of it documented on the streets with blue and yellow markers - as officials begged the public to come forward with tips and videos that could help find the suspects.

Councilmember Katie Valenzuela, who represents the area, said she’s fielded many phone calls reporting violence in her district during her 15 months in office.

“I’m heartbroken and I’m outraged,” she said. “Our community deserves better than this.”

Sunday’s violence was the third time this year in the U.S. that at least six people have been killed in a mass shooting, according to a database compiled by The Associated Press, USA Today and Northeastern University.

President Joe Biden called for action on gun crimes in a statement Sunday.

“Today, America once again mourns for another community devastated by gun violence,” Biden said. “But we must do more than mourn; we must act.”

Sacramento has endured two mass shootings in the last five weeks.

On Feb. 28, a father killed his three daughters, a chaperon and himself in a Sacramento church during a weekly supervised visitation. David Mora, 39, was armed with a homemade semiautomatic rifle-style weapon, even though he was under a restraining order that prohibited him from possessing a firearm.

The area where Sunday’s killings occurred is on the outskirts of the city’s main entertainment district and has many bars and restaurants.

Videos on social media showed what appeared to be an altercation before the gunfire in California’s capital city.

Sgt. Zach Eaton, a police spokesperson, said investigators don’t know if that fight led to the shooting.

A video posted on Twitter showed people running amid the sounds of rapid gunfire.