A gunman attacked a grocery store in an upscale Tennessee suburb on Thursday afternoon, killing one person and wounding 12 others before he was found dead of an apparent self-inflicted gunshot wound at the store, authorities said.

Collierville Police Chief Dale Lane said the shooting broke out at a Kroger grocery in his suburban community about 30 miles (50 kilometres) east of Memphis. He said the gunman shot 13 others and himself, and that 12 of the victims were taken to hospitals, some with very serious injuries.

One Kroger worker, Brignetta Dickerson, told WREG-TV she was working a cash register when she heard what at first she thought were balloons popping.

“And, here he comes right behind us and started shooting,” Dickerson said. “And, he kept on shooting, shooting, shooting. He shot one of my co-workers in the head and shot one of my customers in the stomach.”

Lane said police received a call about 1:30 pm about the shooting and arrived almost immediately, finding multiple people with gunshots when they entered the building.

He said a police SWAT team and other officers went aisle to aisle in the store to find people who sought cover or were in hiding, taking them to safety. He said the shooter, whom he described as male, was found dead of an apparent self-inflicted gunshot wound.

The identities of the shooter and the victims were not immediately released. At a news briefing Thursday evening, Lane declined to reveal more about the suspect, citing the ongoing investigation, including search warrants that will be carried out.

“We’re going to carry this thing as far as we can to see and make sure that there’s no else involved,” Lane said, adding that there was “no credible evidence” that there was a second shooter.

The chief also said, “As far as we know there wasn’t any other incident that led up to this.”

Dickerson, the employee, said her co-worker, who is in his 20s, was shot in the head and said he wanted his mother to be notified.

“I left her a voicemail that he was alert and talking,” Dickerson said, adding that she was still trying to reach her later in the day.

“I was walking back towards the floral department and I heard a gunshot,” she said. “It sounded like it was coming from the deli. And I ran out the front door and they had already shot the front door.”

Lane called it a sad day for his department in his initial briefing with reporters.

“I’ve been involved in this for 34 years and I’ve never seen anything like it,” he said Thursday afternoon.

The suspect’s vehicle was in the store’s parking lot and remained there as part of the investigation, the chief said.

He added that investigators were seeking to piece together how the shooting unfolded, adding, “It’s going to take a little bit before we know what happened.”

“Let’s get through the investigation,” Lane said. “Remember, we’re two hours away from the most horrific event that’s occurred in Collierville history.”

Collierville is a growing suburb of more than 51,000 people with a median household income of about $114,000, according to US census figures. Set in a rural and historic area, the town square has largely become known for its boutiques and bed and breakfasts.

Earlier this year, Tennessee became the latest state to allow most adults 21 and older to carry handguns without first clearing a state-level background check and training. The measure was signed into law by Republican Gov. Bill Lee over objections from some law enforcement groups and gun control advocates concerned the measure would possibly lead to more gun violence.

The Kroger Co., based in Cincinnati, Ohio, issued a statement that it was “deeply saddened” by the shooting and was cooperating with law enforcement. The company in 2019 asked its customers not to openly carry guns while visiting its stores.

A Kroger spokesperson said the Collierville store will be closed until further notice.