US shooting leaves 13 dead_美文_趣味英语-查字典英语网

US shooting leaves 13 dead

Monday's shooting left Washington on edge and there was a security scare hours later at the White House when a man who apparently threw fire crackers over a fence at the US president's residence was swiftly arrested.

Even hours after the mass shooting - the deadliest on a military installation in the US since the tragedy at Fort Hood, Texas, in 2009 - Alexis' motivation for opening fire 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 said on condition of anonymity.

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.

His work as a naval contractor suggested he may have had a pass that could gain him entry to the Naval Sea Systems Command, which oversees shipbuilding programs carried out by defense firms.

It was unclear if the military or HP had been aware of Alexis' brushes with the law, including reportedly two shooting incidents, before he was hired for the IT job.

The shooting sparked a massive show of force as police and federal agents descended on the Navy Yard on the Anacostia River, less than 3 kilometers from the Capitol.