By Jeremy Herb and Jonathan Easley - 09/16/13 09:59 PM EDT
Reports varied throughout the day about how many shooters were involved with the killings, with District Chief of Police Cathy Lanier telling reporters at one point that there were two possible other shooting suspects.
Adding to the confusion, the Senate abruptly went into lockdown for more than an hour on Monday afternoon — several hours after the Navy Yard shooting had occurred — in what was described as cautionary move. The House did not go into lockdown.
The FBI said the suspect killed was Aaron Alexis, 34, of Ft. Worth, Texas. He was identified as a former sailor who enlisted in the Navy in 2007 and served until 2011, according to biographical information released by the Navy. He reached the rank of petty officer 3rd class.