DeWayne Craddock, an engineer who had worked for the City of Virginia Beach for about 15 years, notified his superiors on Friday that he intended to quit.
Then at around 4 p.m., he embarked on a rampage in Building No. 2 of the Virginia Beach Municipal Center, turning its offices and corridors into a battleground. When it was over, 12 people lay dead and Mr. Craddock was fatally wounded.
As the authorities on Sunday shared a more detailed accounting of the siege, they also acknowledged for the first time that the gunman’s employment had been nearing its end. But they said he had not been forced to resign.