The man who injured eight people during a stabbing attack at a Minnesota shopping mall asked at least one of his victims whether they were Muslim and made reference to Allah, authorities said.
However St Cloud Police Chief Blair Anderson declined to call the attack an act of terrorism, saying the motive for the attacks isn't known yet.
"We will be diligent and get to the bottom of this," he said. "Starting tomorrow, things won't be the same here."
The victims were taken to hospital with non-life-threatening injuries after the attack at the Crossroads Center was first reported around 8.15pm Saturday.
Mr Anderson said an off-duty police officer from another jurisdiction shot and killed the unidentified suspect, who was armed with a knife and wearing a private security firm uniform.
Local police had three previous encounters with the suspect, most for minor traffic violations, Mr Anderson said, adding that the FBI had offered to help with the investigation.
He said authorities "have no reason to believe" anyone else was involved in the attack.
The stabbings occured in several places within the mall, including corridors, businesses and common areas.
The mall remained on lockdown following the incident, but authorities expected those remaining inside to be released early Sunday. "The entire mall is an active crime scene," Mr Anderson said.
Photos and video of the mall taken hours after the incident showed groups of shoppers waiting to be released, including some huddled together near a food court entrance.
St Cloud is about 70 miles (112.65 kilometers) northwest of Minneapolis.
