A passenger with a gun in his checked luggage opened fire in the baggage claim area at the Fort Lauderdale airport Friday, killing five people and wounding eight before throwing his weapon down and lying spread-eagle on the ground, authorities and witnesses said. Esteban Ruiz Santiago, 26, the suspect in the deadly shooting at Fort Lauderdale-Hollywood International Airport.(AP) The gunman — identified by authorities as 26-year-old Esteban Santiago, an Army National Guard veteran who served in Iraq but was demoted and discharged last year for unsatisfactory performance — was immediately taken into custody. His brother said he had been receiving psychological treatment recently. Authorities said the motive was under investigation. Santiago arrived in Fort Lauderdale after taking off from his hometown of Anchorage, Alaska, aboard a Delta flight Thursday night, checking only one piece of luggage — his gun, said Jesse Davis, police chief at the Anchorage airport. At Fort Lauderdale, "after he claimed his bag, he went into the bathroom and loaded the gun and started shooting. We don't know why," said Chip LaMarca, a Broward County commissioner who was briefed by investigators. In 2013, a gunman with a grudge against the Transportation Security Administration shot and killed one of the agency's screeners and wounded three others during a rampage at Los Angeles International Airport. Last November, an airline worker was shot and killed near an employee parking lot at Oklahoma City's airport, and in 2015 a machete-wielding man was shot to death after he attacked federal security officers at the New Orleans airport. In the Fort Lauderdale attack, Lea said the gunman said nothing as he "went up and down the carousels of the baggage claim, shooting through luggage to get at people that were hiding." The killer had a handgun and went through about three magazines before running out of ammunition, Lea said. Sheriff Scott Israel said five people were killed and eight were wounded. Their condition was not disclosed. He said the gunman was arrested unharmed, with no law enforcement officers firing any shots, and was being questioned by the FBI. Santiago's brother, Bryan, told The Associated Press that his brother had been receiving psychological treatment in Alaska. Esteban Santiago was deployed to Iraq in 2010 and spent a year there with the 130th Engineer Battalion, according to Puerto Rico National Guard spokesman Maj. Paul Dahlen. He later joined the Alaska National Guard.