At least 12 people were killed and four others injured when a disgruntled employee opened fire in a municipal centre building in the US state of Virginia. The attacker was shot dead after a police confrontation, authorities said.The shooting suspect identified as DeWayne Craddock, who worked as a certified professional engineer for the city of Virginia Beach in the Public Utilities Department, opened fire on Friday in the Building 2 of the municipal centre, CNN quoted Police Chief James Cervera as saying.Building 2 of the Virginia Beach Municipal Centre houses the operations building for the city, which include multiple departments.Cervera said the 40-year-old shooter was confronted shortly after opening fire on multiple floors. There was an exchange of gunfire with officers after which he was shot dead.The police chief confirmed that a .45 caliber pistol and several empty extended magazines were found near the gunman.The suspect is thought to have purchased the firearms legally, according to initial investigation."This is the most devastating day in the history of Virginia Beach," said Mayor Bobby Dyer. "The people involved are our friends, co-workers, neighbour, colleagues."According to Virginia Beach Vice Mayor James Wood, people can take guns into public buildings, but not schools or courts in the city.Virginia Governor Ralph Northam described the incident as a "tragic day" for the city and the state.State Senator Tim Kaine tweeted that he was devastated by the news, CNN reported.Singer Pharell Williams, who grew up in Virginia Beach, said in a tweet: "We are praying for our city, the lives that were lost, their families and everyone affected..."Friday's incident is the deadliest mass shooting in the US since November 2018.In that shooting, 12 people were killed at the Borderline Bar & Grill in Thousand Oaks, California. Officials said that gunman, Ian David Long, shot an unarmed security guard outside the bar, went in and continued shooting, injuring other security workers, employees and patrons. Long died by suicide.