SACRAMENTO — The six people killed in an eruption of gunfire in downtown Sacramento over the weekend, one of the worst mass killings in the city’s history, ranged in age from 21 to 57, the county coroner’s office said Monday.

It was still unclear by midmorning on Monday who was behind the shooting, which took place outside nightclubs in the early hours of Sunday. The chief of police, Katherine Lester, said several gunmen were involved.

The dead, three women and three men, were identified by the coroner’s office as Johntaya Alexander, 21; Melinda Davis, 57; Sergio Harris, 38; Joshua Hoye-Lucchesi, 32; Yamile Martinez-Andrade, 21; and Devazia Turner, 29.

Twelve more people were wounded.

The shooting, which occurred a short walk from the State Capitol, stunned a city that has not yet recovered from the pandemic. Sacramento, especially the downtown area, saw a number of restaurants and other shops go out of business, largely because state employees stopped commuting to offices downtown.

Most state employees in the city are still working from home. Even so, downtown Sacramento has seen business revive at night in recent months, residents and business owners said.

“Everybody’s trying to go out and enjoy themselves, everybody’s sick of being inside,” said Anthony Montes, a manager at Rodney’s Cigar and Liquor, a shop on the street where the shootings occurred. When he closed for the night at 11 p.m. Saturday, he felt a heightened energy, Mr. Montes said: “You could sense something. There were too many people out.”

Several popular longtime Sacramento establishments closed down during the pandemic, contributing to a sense of eerie quiet downtown, he said. But as mask mandates have been lifted in recent weeks, Mr. Montes said, the local nightclub scene has boomed.

Sacramento residents said they were shocked by the sheer number of rounds that were fired during the shooting. One local television station that analyzed video taken at the scene counted at least 76 gunshots in less than a minute.

“It woke me up, and I thought it was a war going on out there,” said Anthony Ballard, who lives on the street where the shooting occurred.

“I’ve lived here most of my life,” Mr. Ballard added. “It’s changed during the pandemic.”

Violent crime rose in Sacramento last year, especially murders. The city recorded 55 murders, a 31 percent increase from the year before and the highest level of murders in 15 years.

Ms. Lester, the police chief, said in a statement on Sunday that her department was investigating whether the shooting had any link with a fight outside the nightclubs on Sunday.

“We are aware of a social media video that appears to show an altercation that preceded the shooting,” Ms. Lester said. “We are currently working to determine what, if any, relation these events have to the shooting.”

One stolen firearm was recovered at the scene, Ms. Lester said, adding that a police camera captured parts of the attack.