I remember the DC Navy Yard massacre. The shooter was a computer contractor with DOD as I recall with security clearance, but got fired or resigned. Remember he still had his ID Credentials to gain easy access to the yard. Believe the shooter was also an Army Veteran, but did not receive an honorable discharge, just a general under honorable conditions.
Sorry he was a Navy Veteran who should have gotten only a general discharge due to repeated misconduct, but due to political correctness got an honorable discharge.