Walmart says it is working closely with investigators to try to determine why a shooter opened fire at one of its stores in Ohio and wounded four people before killing himself.

The attack was reported at around 8:30 p.m. Monday at the Walmart in Beavercreek, a town of about 50,000 in the Dayton metropolitan area.

Three women and a man were taken to area hospitals, where three of the victims remained in critical condition on Tuesday, police said in a statement. The fourth victim had injuries that were not life-threatening.

Authorities said the shooter died after apparently shooting himself. His name and a motive for the attack have not yet been released.

Police earlier said on social media that the store had been cleared and secured and there wasn’t any “active threat.”

“We’re heartbroken by what’s happened at our Beavercreek, Ohio store. This remains a developing situation, and we’re working closely with investigators on the scene,” Walmart, the world’s largest retailer, said in a statement.

The shooting happened a day after two people were shot and killed outside a Walmart in south Anchorage, Alaska. Police are still searching for a suspect in that case. The store was evacuated before closing for the day, and officers helped people reach their vehicles.

In November of last year, a Walmart supervisor in Chesapeake, Virginia, fatally shot six employees on the Tuesday before Thanksgiving. The shooter died at the scene of an apparent self-inflicted gunshot wound, police said.

In 2019, a white gunman killed 23 people at a Walmart in El Paso in a racist attack that targeted Hispanic shoppers.

The store in Ohio where Monday’s shooting took place was the scene of a fatal shooting involving police almost 10 years ago.

A white police officer shot 22-year-old John Crawford III, after he picked up an unpackaged pellet rifle he found on a shelf in August 2014. The family of the Black man reached a settlement of $1.7 million with the city of Beavercreek. The settlement included changes in police policy.

Walmart launched a computer-based active shooter training in 2015, which focused on three pillars: avoid the danger, keep your distance and lastly, defend. Then, in 2019 after the shooting in El Paso, Walmart discontinued sales of certain kinds of ammunition and asked that customers no longer openly carry firearms in its stores. It now sells only hunting rifles and related ammunition.

(AP)