Officials announced Sunday that he was not terminated but gave in his two week resignation notice via email Friday and went to work as usual

DeWayne Craddock, 40, resigned from his 15-year job with the Virginia Beach's public utilities department Friday morning, hours before he launched his deadly shooting

The Virginia Beach gunman who killed 12 as he unleashed a hail of bullets in a government building on Friday had resigned from his job just hours before the deadly attack.

Gunman DeWayne Craddock, 40, had handed in his two week notice of resignation on Friday morning via email after working as an engineer for 15 years.

Just hours later, at 4pm, he opened fire, killing 12 people, including one of his own supervisors, at the Virginia Beach Municipal Center.

Speaking of Craddock's resignation, City Manager Dave Hansen said: 'He notified his chain of command that morning. My understanding is he did that via email.'

He said officials are now trying to determine where that letter is.

Hansen said that Craddock had not been fired and described him as a satisfactory worker in good standing in his department. He had no disciplinary issues in the workplace.

But a source previously told the New York Times that Craddock had recently been getting into physical “scuffles” with other city workers and had got into a violent altercation on city grounds in the last week.

Officials announced Sunday that he was not terminated from his city job but gave in his two week resignation notice via email Friday and went to work as usual. Police Chief James A. Cervera pictured above

'He notified his chain of command that morning. My understanding is he did that via email,' City Manager Dave Hansen said at a press conference Sunday morning. He said officials are now trying to determine where that letter is

Craddock was described as a satisfactory worker by his employers. He's also been described as a 'disgruntled employee'. He worked at Virginia Beach Municipal Center where he launched his shooting on Friday

His resignation and apparent good work standing makes his motive behind the devastating shooting all the more unnerving.

'There weren’t any clues I was aware of or that were being funneled to the top,' director of Virginia Beach's public utilities department Bob Montague said. 'I certainly didn’t have a reason to believe that anything like this would happen.'

Craddock has previously been described as a 'disgruntled employee' and a 'loner ex-National Guardsmen'.

Police Chief James A. Cervera said officials are looking at his professional and personal life for a possible motive.

Craddock had bizarrely chatted with a colleague as he brushed his teeth in an office bathroom just moments before the rampage began on Friday.

Shots were fired just after 4pm and cops arrived to the scene within two minutes of the call.

Craddock killed a woman who was on her way out of the office, used his badge to access the building's second floor, and opened fire indiscriminately.

Cops found him about five to eight minutes after entering the building and engaged in a 'gun battle' with Caddock on the second floor of Building 2 - which was built in the 1970s and was described by police as a 'honeycomb maze'.

Craddock, pictured left in his school yearbook in 1995 and right in 1996, was spotted brushing his teeth in the office restrooms where he exchanged pleasantries with a colleague and wished him a good weekend

Boards secure the front door of a house of shooting suspect DeWayne Craddock on Saturday

Samantha Anderson (front), six, looks up at her mother Christine Anderson, 40, as she pray's in front of the memorial near the site of Friday's mass shooting at the Virginia Beach Municipal Center

DeWayne Craddock, a longtime city employee, opened fire at the building Friday before police shot and killed him

David Moore wipes tears away while praying with community members, left. Tears run down the face of Deta Green, right

Craddock killed 12 people in his frenzied attack. Mourners pictured about praying at a parking lot near the Virginia Beach Municipal Center on Saturday

Cervera said the number of rounds fired was 'well into the double digits'.

The gunman shot as he moved, firing through doors and walls. At 4.19pm he hit an officer, who was wounded but saved by his protective vest.

Finally cops got to him in an office where they broke down the door and engaged in gunfire exchange. He was finally subdued, taken into custody, and administered First Aid.

He died on his way to a nearby hospital. A total of 36 minutes had passed from the time of police dispatch to the time the suspect was in custody and administered aid.

Within an hour of the attack, all the wounded had been transported for emergency care.

Twelve people were tragically killed in Friday's shooting. They are (from top left to bottom right): Laquita C. Brown, Ryan Keith Cox, Tara Welch Gallagher and Mary Louise Gayle. Middle row from left are Alexander Mikhail Gusev, Joshua O. Hardy, Michelle 'Missy' Langer and Richard H. Nettleton. Bottom row from left are Katherine A. Nixon, Christopher Kelly Rapp, Herbert 'Bert' Snelling and Robert 'Bobby' Williams

Craddock wielded two legally purchased .45 caliber pistols and used a suppressor, also known as a 'silencer', to mute his shots as he opened fire on three floors of the city building before he was killed by police.

Craddock enlisted in the Virginia National Guard in April 1996, according to spokesman A.A. Puryear, after graduating in 1996 from Denbigh High School in Newport News.

He was assigned to the Norfolk-based 1st Battalion, 111th Field Artillery Regiment, 116th Infantry Brigade Combat Team as a 13B cannon crew member.

Yesterday, officials released the name of the 12 victims. They are: LaQuita Brown, Tara Gallagher, Mary Gayle, Alexander Gusev, Katherine Nixon, Richard Nettleton, Christopher Rapp, Ryan Cox, Joshua Hardy, Michelle 'Missy' Langer, Robert 'Bobby' Williams and Herbert 'Bert' Snelling.

The investigation is ongoing.