Charleston - A fired dishwasher shot and killed a chef and held a person hostage for about three hours before he was shot by police at a crowded restaurant in a tourist-heavy area of downtown Charleston on Thursday, authorities and one of the restaurant's owners said.The hostage was freed unharmed, Mayor John Tecklenburg said.The shooting took place at Virginia's restaurant on the usually crowded King Street, a row of shops and nice dining that caters to both tourists and residents in South Carolina's largest and most historic city.Tecklenburg quickly said the shooting was "the act of a disgruntled employee" and not a terrorist attack or hate crime in a city where nine black church members were killed by a white man two years ago."This was a tragic case of a disturbed individual, I think, with a history of some mental health challenges," Tecklenburg said at a news conference.'Everybody started running'Authorities did not release the names of the gunman or the employee he killed. They initially said they believed there were "a couple" or a "small number" of hostages.The shooting was reported shortly after 12:00 on Thursday.Peter Siegert IV and his family from Galesville, Maryland, had just been served fried chicken at the restaurant when he noticed waitresses and kitchen workers leaving hurriedly through the front door.Then he saw a man in a backward ball cap and an apron enter the dining room from the back of the restaurant."He said: 'There's a new boss in town,'" Siegert said."I don't think anybody realised he had a gun until after he locked the door. And then he turned around and had a revolver in his hand. He never pointed it at any of the patrons. He held it by his side."The man told all the customers to get onto the floor, Siegert said, then directed them to crawl to the back of the restaurant - where the rear exits remained unlocked."He told everybody to get out," he said. "Everybody started running for the doors."One of the restaurant's owners, John Aquino, told WCSC-TV that a dishwasher who had been fired came back to the restaurant and shot a chef to get revenge.The restaurant was packed with a lunchtime crowd and the first officers to arrive were able to get the man who was shot and a number of diners out safely, interim Charleston Police Chief Jerome Taylor said.The site is a few blocks away from Emanuel AME church where nine black members of a church were killed by a white man during a June 2015 Bible study.Dylann Roof was sentenced to death in the case.It is also just several blocks from where more than 100 cruise ships dock in Charleston each year.