COLLIERVILLE, TENN. • 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 kilometers) 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 p.m. 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.

“We found people hiding in freezers, in locked offices. They were doing what they had been trained to do: run, hide, fight,” the chief said without elaborating.

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 that, “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.

Another employee, Glenda McDonald, described the chaotic scene to WHBQ-TV.

“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.”