The resignation letter that the gunman sent hours before the shooting at a Virginia Beach municipal building showed no sign of the rampage that was to come.

The email, obtained by Fox News, was brief and unremarkable. DeWayne Craddock, 40, cited “personal reasons” for his resignation without elaborating.

He was an employee “in good standing” and showed “satisfactory” job performance, City Manager Dave Hansen said.

VIRGINIA BEACH POLICE ZERO IN ON SHOOTER'S WEAPONS CACHE AND JOB BACKGROUND

“The document itself is part of the investigative file,” city Communications Director Julie Hill said in an email. “If detectives are able to clear it for release, we will provide it.”

“Right now we do not have anything glaring,” added Police Chief James Cervera. “There’s nothing that hits you right between the eyes. But, we are working on it.”

Twelve people were killed and several others wounded after Craddock, an engineer with the Virginia Beach utilities department, opened fire on his co-workers as they finished up their work week Friday.

Craddock was killed during a gunbattle with police.

Cervera described a chaotic scene as officers entered the building Friday and pursued the assailant through a tightly packed warren of offices that the chief likened to a maze or a honeycomb. They exchanged fire in a protracted gunbattle. Cervera did not know how many rounds were fired but said it was “well into the double digits.”

“In the police world, anything more than three to five shots is a long gunbattle,” he said.

A medical examiner will determine whether he was killed by an officer’s bullet or his own, the chief said.

There was no indication he targeted anyone specifically. Cervera said investigators weare retracing the gunman’s activities on the day of the attack, using his electronic keycard to track his movements through secure areas of the building. They also were reviewing his personal and professional lives trying to find a motive.

On Monday, a makeshift memorial made up of bouquets, flags, teddy bears and crosses bearing the names of the shooting’s victims stood at one entrance to the municipal center. A small group of city employees cried and hugged each other as they left flowers by one of the crosses. Volunteers with comfort dogs were on hand.

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Gun violence awareness moment of silence is set for later Monday afternoon in Congress. Rep. Elaine Luria, D-Va., will lead the moment of silence for the Virginia Beach victims Tuesday.

Fox News' Mark Meredith and The Associated Press contributed to this report.