TWIN FALLS, Idaho (AP) — The suspect in a fatal shooting at a fast-food restaurant in Idaho died of a self-inflicted gunshot wound, police said Sunday, crediting an off-duty officer and a citizen with firing shots that diverted him away.

Investigators are confident that the gunman, identified as 24-year-old Chad Williams, acted alone during the shooting Saturday in Twin Falls, Police Chief Matthew Hicks said at a news conference.

In all, three people died and seven others were injured at the recently opened restaurant in the southern Idaho city of about 56,000 people. Authorities said Sunday that two of the injured were treated at a hospital and released, three were listed as stable, and two were in critical condition.

Hicks said an off-duty state trooper and an armed citizen — whose identities weren’t immediately disclosed — both fired back and diverted the gunman away from the restaurant.

“We believe their actions helped drive the suspect away from the scene, preventing further casualties,” the chief said. “We want to take a moment and commend the actions of the off-duty officer and the citizen, and their heroic action to stop this incident."

Hicks said detectives are working to determine Williams’ motivations, and said the suspect’s family was cooperating fully with law enforcement.

He also warned of misinformation spreading online identifying a different man as the shooter, saying the man had “no involvement in this incident whatsoever.”

In-N-Out worker among the victims
One of those killed was an employee, the fast-food chain’s owner said.

“My heart is broken, my chest is heavy, my eyes burn from the tears I’ve shed. We lost one of our beautiful Associates tonight,” In-N-Out owner Lynsi Snyder said in a statement released early Sunday on social media. “In-N-Out will be mourning with the families and praying for them as they tread through a very painful season.”

The FBI on Sunday encouraged the public to submit images and videos related to the shooting Saturday in Twin Falls that left seven other people wounded, some critically.

The In-N-Out had opened just about a week earlier, on July 24, as part of the California-based company’s recent expansion to Idaho.

Snyder did not identify the worker. Officials were still trying to notify relatives of victims and so were not yet releasing the names, ages or other details about the people hurt in the shooting, Twin Falls spokesperson Josh Palmer said Saturday.

Police who responded to the shooting found the body of the suspected gunman in an area near the restaurant, Palmer said.

Palmer said investigators were interviewing witnesses to the shooting. The restaurant is in a busy shopping plaza, and hundreds of people were in the area when it happened around 2 p.m.

Witnesses describe chaotic scene
Lane Koehn, 34, said he was at a stoplight near the In-N-Out when he saw a person with an AR-style rifle emerge from the drive-thru. A man with a pistol started firing at the shooter.

He then saw someone in an In-N-Out uniform drag a person, also wearing a uniform, bleeding from a gunshot wound to her chest across the parking lot. The employee, Koehn and the man with the pistol stayed until paramedics arrived for her.

“She was pretty bad off, but I don’t know. I hope she made it,” Koehn said.

He said the shooter fired at least three or four rounds and it was not clear whether or not anyone in particular was targeted.

Video taken by a driver from across the street captured a shooter, who appeared to be dressed in black, walking up to a white car carrying a long rifle, opening the driver-side door and popping the trunk. The person then walked to the trunk and reached inside. At that point the driver who shot the video left quickly, fearing that the man might be getting more weapons.

Twin Falls resident Haley Dodaro, 43, and her mother went to In-N-Out for lunch Saturday afternoon. While waiting in the drive-thru line, they saw people running across the road and workers bolting out of the restaurant. At first, Dodaro thought there might have been a fire, but then a man directing traffic in a reflective vest said there was a shooter.

“So that’s when we knew there was a shooting. People were running out crying and screaming. It was very scary,” Dodaro said in a text message to The Associated Press.

Employee told people to get down
Nayeli Rodriguez, 40, of Burley, was inside waiting for food with her daughters when she heard shots from the kitchen. An employee said it was a shooting and told people to get down. Rodriguez said an older man tried to protect her and her daughters, and they were among the last to run outside.

“We were trying to get as far as we could and some angels let us in their car,” Rodriguez said, also via text message. “I left my car there in the parking lot.”

Twin Falls is about 130 miles (205 kilometers) southeast of Boise and about 75 miles (120 kilometers) north of the Nevada border.