Over the radio, they desperately pleaded for the electronic cards and talked of bringing in a sledgehammer, an explosive charge or other means of breaking down the doors.

The gunman who opened fire inside a Virginia Beach government building, killing 12 people, had notified a superior of his intention to leave his job, officials said Saturday.

Virginia Beach Police Chief James Cervera identified the gunman as DeWayne Craddock, who was employed as an engineer with the city’s public utilities department. Craddock died in a gun battle with police.