In-N-Out Burger mass shooting motive still in question

Investigators in southern Idaho are still piecing together why a 24-year-old man opened fire at an In-N-Out Burger in Twin Falls over the weekend, killing three people and injuring seven others before turning the gun on himself. 

Big picture view:

The shooter was identified Sunday as Chad Williams, and detectives with the Twin Falls Police Department determined that he acted alone. Police Chief Matthew Hicks noted that Williams’ family is cooperating fully with the investigation. 

What we know:

The shooting happened Saturday at an In-N-Out Burger that had opened a little more than a week earlier and is near a busy shopping center in Twin Falls, a southern Idaho city of around 56,000 people. 

Hicks credited an off-duty state trooper and another individual, who both fired at Williams, with diverting him from the fast-food restaurant.

RELATED: Social Security COLA 2027: How much payments are projected to increase 

What we don't know:

The investigation into the motive remains ongoing, authorities said. As of Monday afternoon, they have not released the victims’ names, and a Twin Falls spokesperson explained that authorities were still trying to notify next of kin. 

An In-N-Out worker was killed in the shooting, the chain’s owner, Lynsi Snyder, wrote in a statement that did not identify the employee. Police said Sunday that two of the people suffered critical injuries, three others whose conditions have been stabilized remained in the hospital, and the other two had been released.

Dig deeper:

One witness, Lane Koehn, described seeing someone holding an AR-style rifle near the drive-thru before a man with a pistol started firing at the shooter. Koehn also recounted seeing someone in an In-N-Out uniform dragging a woman who was also wearing the restaurant’s uniform out of the restaurant and waiting, along with the person with a pistol, for paramedics to arrive.

U.S.