Navy orders probe of DC rampage as shooter’s remains released

Surveillance video shows Aaron Alexis during attack 2:13

The Navy ordered an investigation into the deadly Washington Navy Yard shooting on Thursday, and the D.C. medical examiner released the gunman’s remains.

Navy Secretary Ray Mabus issued a memo ordering the in-depth probe, which will include a detailed review of the events leading up to the shooting in which Aaron Alexis, a former petty officer, was able to enter the Navy Yard with a shotgun and roam the halls looking for targets.

The investigation will also look into the shooter’s mental health background as well as his military record, The Associated Press reported.

The FBI is also conducting its own criminal probe of the case.

This image released by the FBI shows a photo of Aaron Alexis, who police believe was a gunman at the Washington Navy Yard shooting in Washington, Monday morning, Sept. 16, 2013, and who was killed after he fired on a police officer. At least one gunman launched an attack inside the Washington Navy Yard, spraying gunfire on office workers in the cafeteria and in the hallways at the heavily secured military installation in the heart of the nation's capital, authorities said. (AP Photo/FBI)

Burning questions remain on circumstances surrounding the shooting, including whether Alexis’ employer, a Hewlett-Packard subcontractor, The Experts, had warned the military about concerns about Alexis’ mental stability.

Navy officials have said they could find no record the company alerted the Navy.

Alexis killed 12 people and wounded four others in a hours-long rampage through Naval Sea Systems Command on Sept. 16 before he was killed in a shootout with police on the third floor of Building 197.

Also on Thursday, a spokeswoman for the Chief Medical Examiner’s Office in Washington, D.C., confirmed to NBC News that an autopsy had been completed on Alexis' body and his remains had been released.

She declined, however, to say who claimed the body or provide the results of the autopsy.

On Wednesday, HP issued a statement that it was cutting ties with The Experts over its “failure to respond appropriately” to Alexis’ mental health issues. That move came shortly after the FBI disclosed that Alexis had been suffering from a “delusional” belief that he was being controlled by “low frequency electro-magnetic waves.”

Rhode Island police said last week it had reported concerns to the Navy last August after Alexis called them to complain he was hearing voices and believed he was under surveillance while he worked on another job for IT contractor in that state.

Mabus named Adm. John Richardson, head of the Navy’s Nuclear Propulsion Program, to lead the new investigation, which will look into whether Navy policies were followed regarding security clearances, building protection and emergency responses.

Both the AP and Reuters said they had obtained the memo issued by Mabus ordering the investigation, which called for the probe to be finished by Nov. 6.

Michael Isikoff of NBC News and The Associated Press and Reuters contributed to this report.