Authorities said the standoff started around 10:30 a.m. PT when Fuaed Abdo Ahmed, 20, took two women and a man captive at the Tensas State Bank branch. During hostage negotiations, authorities were able to get Ahmed on the phone with a friend in Alaska, Louisiana State Police superintendent Col. Mike Edmonson said. Ahmed eventually released a female hostage.
Ahmed had written a letter "detailing exactly what he was going to do," Edmonson said.
"He was mad at people that he said were mean to him," he said. "He had voices in his head."
Edmonson said the man grew increasingly erratic as negotiations went on. One of Ahmed's demands was that authorities remove a device that he believed had been implanted in his head, Edmonson said.
Eventually, the gunman told negotiators he was going to kill the two remaining hostages. State police entered the building just before 10 p.m. PT. That's when Ahmed shot the two hostages and then police shot and killed him, Edmonson said.
Both hostages were shot in the upper body. Authorities have not identified the male victim who was killed. The second hostage who was shot was taken to a hospital in critical condition.
Edmonson said there was no indication Ahmed had any history with the hostages, who were bank employees, and authorities did not know why he picked the bank. The bank sits across the street from a service station owned by Ahmed's family.
Ahmed's parents were from Yemen, but he was a U.S. citizen and there was no indication that he had a political or religious motive, Edmonson said.
On a Facebook page under Ahmed's name, Ahmed describes himself as a native of Fresno, Calif. In a post on Sunday, he displays a cartoon strip that focuses on an apparent hostage situation.
The Associated Press contributed to this report.