Surveillance video released Friday shows a gunman at an Idaho In-N-Out Burger killing one of his three victims last week by firing through a drive-up window before shooting more people outside the fast-food restaurant.

Police in Twin Falls said at a news conference that they still don’t have a motive for the shooting last Saturday. Seven people were wounded. The gunman, Chad Williams, 24, killed himself.

Video shows Williams walking up to the drive-thru window four times to fire shots. A worker at the window died of gunshot wounds. A second victim died outside the restaurant and another in a nearby visitors center parking lot.

“What happened here was violent, frightening and deeply traumatic,” Twin Falls Police Chief Matthew Hicks said.

It should have been a “normal Saturday afternoon,” he said. “Employees showing up for work. Visitors coming to see our beautiful city. Instead they were confronted with chaos, fear and now loss.”

Hicks praised the work of an off-duty state trooper and a former police officer, A.J. James, who was wounded while confronting Williams.

James acted “heroically and unbelievably” to try to slow down the shooter, Hicks said.

The In-N-Out had opened in July as part of the chain’s expansion into Idaho.

Police identified those killed as Ashley Garibay, 23, of Stockton, California; Dale Schultz, 66, of Salt Lake City; and Christopher Claunch, 59, of Hagerman, Idaho.