An investigation continues Monday morning after Ontario police officers shot and killed an armed man inside a Stater Bros. market.
Employees and shoppers were inside the store Sunday night when the man showed up, but he never fired any shots.
Ontario Police Detective Melissa Ramirez told KPCC media partner NBC-4, that they're still looking for answers.
"What was he thinking? Why would he come to the store armed with a shotgun? What was his motivation?" she said. "Obviously he chose it when it was open, and there were people present, but clearly it wasn't something that most rational people would choose to do."
Nobody else was injured. It's still unclear what led officers to open fire.
Check back for updates to this story.