Investigators have identified two .45 caliber pistols used in Friday's mass shooting at a municipal building that killed 12 people, a U.S. official said Saturday.

All indications were that the guns were bought legally, Ashan Benedict, regional special agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives, a federal law enforcement organization within the U.S. Department of Justice, told a press conference.

One gun was bought in 2016 and the other was bought last year, according to Benedict.

People gather to pray during a vigil in response to a fatal shooting at a municipal building in Virginia Beach, Virginia, Saturday, June 1, 2019. A longtime city employee opened fire at the building Friday before police shot and killed him, authorities said. [Photo: AP]

He also said two other weapons were found at the home of the gunman, identified by police earlier in the day as 40-year-old DeWayne Craddock, a city engineer who had been employed with Virginia Beach's public utility department for the past 15 years.

The shooting massacre that Craddock carried out on Friday afternoon led to 12 fatalities and four injuries.

Craddock was killed in a "long gunbattle" with police officers.