Police identified the alleged gunman as Aaron Alexis of Fort Worth, Texas, who served in the Navy from 2007 to 2011 before becoming a defense subcontractor for computer giant Hewlett-Packard.
US authorities probing the shooting spree at Washington’s Navy Yard, which local news outlets early on Tuesday reported also injured 14, said the gunman appeared to have acted alone.
“We do now feel comfortable that we have the single and sole person responsible for the loss of life inside of the base today,” police chief Cathy Lanier said late on Monday.
The Federal Bureau of Investigation appealed to the public for information on the 34-year-old, whose military service was marked by disciplinary problems and who reportedly had once been arrested but not charged in Texas for shooting a bullet through his apartment ceiling.
“No piece of information is too small. We are looking to learn everything we can about his recent movements, his contacts and his associates,” said Valerie Parlave, assistant director of the FBI’s Washington field office.
The FBI released a photo of Alexis, who held the rank of an Aviation Electrician’s Mate 3rd Class and had served full-time in a logistics support squadron in Fort Worth, according to the Navy.
The shooting left Washington on edge and there was a security scare hours later at the White House when a man who apparently threw firecrackers over a fence at the US president’s residence was swiftly arrested.
Even hours after the shooting, Alexis’s motivation for opening fire, reportedly with an AR-15 assault rifle, was unclear. His four-year stint in the Navy was troubled, officers said.
“There is definitely a pattern of misconduct during his service,” a US military officer, who spoke on condition of anonymity, told AFP.
Friends in Texas told US media that Alexis had an interest in Buddhism and was conversant in the Thai language and had thought about moving to Asia.
Most recently, Alexis was employed as an IT subcontractor for a company called “The Experts,” which was working on a Hewlett-Packard contract to upgrade equipment for an intranet network used by the US Marine Corps and Navy, HP said in a statement.