WASHINGTON (AP) — The decision to grant a security clearance to a man who later killed 12 people at the Washington Navy Yard was made without a review of a critical police report, but background investigators still followed the correct standards, the top federal personnel management official told a Senate panel Thursday.

The Senate committee on Homeland Security and Governmental Affairs is investigating the nation’s security clearance system in the aftermath of the Sept. 16 shooting involving Aaron Alexis, a former Navy reservist and IT contractor.