TWIN FALLS, Idaho — A bystander may have saved lives after a gunman opened fire at an In-N-Out Burger on Saturday by distracting the suspect, according to a witness.

Lane Koehn, 34, was at a stoplight just outside the fast-food restaurant when he saw a person with an AR-style rifle emerge from the drive-thru. Bullets struck a car in front of him, and Koehn watched the shooter move through the drive-thru toward his own car, he told NBC News.

“I could tell he was trying to figure out where to go, and somebody in the drive-thru line with a handgun was shooting at him,” Koehn said.

He described the shooter as “panicked” looking around and moving “kind of erratically.” Koehn believes the armed bystander kept the gunman from shooting at more people.

“The shooter was solely focused on him, and [it] allowed us to get out,” Koehn said. “I mean, the car directly ahead of me was getting shot — it gave them time to leave.”

He doesn’t know what happened before he pulled up to the stoplight, but Koehn said that the ordeal he witnessed lasted about 10 to 15 minutes.

Three victims were killed and seven others were injured, two of whom were in critical condition Sunday, Twin Falls Police Chief Matthew Hicks said at a news conference.

The shooter was identified as Chad Williams, 24. He fatally shot himself, Hicks said at a news conference. Williams’ family is cooperating with police, he said. “Their hearts are also broken at this time,” he said.

Hicks said that in addition to the armed bystander, an off-duty state trooper was also there and they engaged the shooter “by returning gunfire towards him.”

“We believe their actions helped drive the suspect away from the scene, preventing further casualties,” Hicks said.

The full circumstances of the shooting and a motive remained under investigation Sunday, Hicks said.

The identities of the victims who were killed were not released because family notifications were still being made, he said.

Koehn described a chaotic scene before police arrived. He said he was able to pull into a parking lot on the other side of the In-N-Out and saw an employee dragging a co-worker who had a gunshot wound to the chest.

“She was just screaming and screaming her name, telling her, ‘Wake up.’ … She was in and out of it,” Koehn said. “She would be up and say a few words and stuff.”

A retired EMT worker happened to be nearby and came over to help while they waited. Once an ambulance arrived, Koehn said, it felt like they got the victim out in just seconds.

Lynsi Snyder, the president of In-N-Out Burger, said a worker was among those killed. It’s unclear whether that is the same employee that Koehn saw receiving medical aid.

“She was taking care of our most important asset — our customers, and her life was taken by a disgusting human who doesn’t value the lives of others or his own,” Snyder said.

In a statement to the community, the Twin Falls Police Department said that residents who call for law enforcement may see members of another agency respond.

“Even in light of yesterday’s incident, we want to assure you that law enforcement services remain available to our community,” the statement said. “We are here if you need us.”

Hicks in Sunday described the scene of the shooting as chaotic.

Minutes after law enforcement arrived, there was an officer-involved shooting but no one was injured, Hicks said.

The office who fired, a Twin Falls police office, are being reviewed, Hicks said.

The department said it is receiving assistance from the Twin Falls County Sheriff’s Office, Nampa Police Department, Caldwell Police Department, Meridian Police Department and Idaho State Police. The FBI also created a digital tip line for members of the public to submit photos, videos and audio recording from the shooting to help investigators.

Dana Griffin reported from Twin Falls, Idaho. Doha Madani reported from New York City.