CHESAPEAKE, Va. (AP) — A Walmart manager opened fire on fellow employees gathered in the break room of a Virginia store, a witness said Wednesday. Six people died in the country’s second high-profile mass shooting in a handful of days.

The gunman, who apparently killed himself, was dead when police found him, said Chesapeake Police Chief Mark G. Solesky said. There was no clear motive for the shooting, which also left four people in the hospital.

The store was busy just before the attack Tuesday night with people stocking up ahead of the Thanksgiving holiday, a shopper told a local TV station.

Employee Briana Tyler said that workers had gathered in the store’s break room as they typically did ahead of their shifts.

“I looked up, and my manager just opened the door and he just opened fire,” she told ABC’s “Good Morning America,” adding that “multiple people” dropped to the floor.

“He didn’t say a word, he didn’t say anything at all,” she said.

Solesky confirmed the shooter, who used a pistol, was a Walmart employee but did not give his name because his family has not been notified. He couldn’t confirm whether the victims were all employees.

“I am devastated by the senseless act of violence that took place late last night in our city,” Mayor Rick W. West said in a statement posted on the city’s Twitter account Wednesday. “Chesapeake is a tightknit community and we are all shaken by this news.”

A database run by The Associated Press, USA Today and Northeastern University that tracks every mass killing in America going back to 2006 shows this year has been especially bad. The U.S. has now had 40 mass killings so far this year, second to the 45 that occurred for all of 2019. The database defines a mass killing as at least four people killed, not including the killer.

The attack at the Walmart came three days after a person opened fire at a gay nightclub in Colorado, killing five people and wounding 17. Earlier in the year, the country was shaken by the deaths of 21 when a gunman stormed an elementary school in Uvalde, Texas.

Tuesday’s shooting also brought back memories of another at a Walmart in 2019, when a gunman police say was targeting Mexicans opened fire at a store in El Paso, Texas, and killed 22 people.

A 911 call about the shooting in Chesapeake, which is Virginia’s second-largest city and lies next to the seaside communities of Norfolk and Virginia Beach, came in just after 10 p.m. The store was open at the time, but Solesky didn’t know how many shoppers were inside or whether the gunman was working.