Emergency vehicles and law enforcement personnel respond to a shooting at an entrance to the Washington Navy Yard, Sept. 16, 2013 in Washington, DC.
Alex Wong—Getty Images
March 18, 2014 11:00 AM EDT

Last year’s deadly shooting at the Washington Navy Yard could have been prevented with better oversight of security clearances and improved on-site security, according to an internal Pentagon investigation released Tuesday.

“Had proper procedures been followed [in vetting personnel for access to secure facilities], the chain of events that led to the incident on September 16,2013, would have been interrupted,” the report says.

The report, coming six months after civilian contractor Aaron Alexis killed 12 people and injured others before being fatally shot by police himself, specifically scolds management at The Experts, the IT company that employed Alexis. He gained access to Building 197 at the Navy Yard with a concealed sawed-off shotgun using valid credentials. The company’s management “decided not to inform the government of adverse information concerning Alexis’ emotional, mental, or personality condition, even when they had concerns that Alexis may cause harm to others,” the report says.

The Experts could not immediately be reached for comment Tuesday morning.

The Navy investigation also found fault with entities up and down the security clearance process, including the Department of the Navy Central Adjudication Facility, which ultimately granted Alexis his security clearance.

The report calls for a larger Navy-wide review of how personnel are vetted and continuously monitored, and of the physical security of the Navy Yard facility, which the investigation found lacking.

The report also calls for the Department of Defense to “establish a single authority” to compile all recommendations stemming from investigations into the 2009 Fort Hood shooting, leaks by Edward Snowden and Chelsea manning, “and other incidents that may be pertinent.”

Contact us at letters@time.com.

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