Updated

Police assembled outside a northeast Arkansas Walmart where a man was later killed after an employee texted her mother saying she expected problems with her ex-husband, who she assumed would be armed.

Trumann Police Chief Chad Henson told the Jonesboro Sun that officers saw Faith Morgan, 21, leaving the store in Trumann Sunday evening with her ex-husband, Gabriel Urrabazo, who had a gun.

Henson said Urrabazo, 22, stepped behind Morgan and held a gun to her head while he negotiated with police.

"They tried and tried to get him to drop the weapon, and they noticed another male coming into the scene," Henson said.

Police said Urrabazo killed Robert Highfill, 35, who tried to save Morgan.

"From the video I have seen, Mr. Highfill tried to bear hug the suspect," Henson said. "The suspect could see him coming as well."

Henson said officers tried to stop Highfill from getting involved, but that "he was committed." He cautioned anyone else from doing the same.

"I fully believe his actions did save Faith and he should be commended. I don't know if (Urrabazo) would have let her go without him doing what he did," Henson said. "But my advice is to never get involved."

Urrabazo surrendered after an hourlong standoff with police. He faces a preliminary charge of first-degree murder, said Henson.

"Just a terrible situation that is unusual for Trumann and we wish this didn't happen," Hansen said.

Trumann is a small town about 120 miles (195 kilometers) northeast of Little Rock.