Of them the employees were shot on Tuesday morning at a Tennessee manufacturing plant, police said.
The shooting took place just before 6 a.m. at SmileDirectClub on Antioch Pike in Nashville, according to the Nashville Metropolitan Police Department.
Police told a news conference broadcast by WKRN that they believed a day shift worker entered the facility during a shift change and opened fire.
Three employees were shot dead and one is in critical condition, police said.
Officers responded to the facility and shot the suspected gunman, police tweeted. He was taken to hospital, where he died, police said at the press conference.
The suspect carried a semi-automatic pistol with an extended magazine and refused officers’ requests to drop the gun, instead pointing it at them, police said.
An “investigation into an active shooter” is underway, police say.
SmileDirectClub said in a statement to local media that it was “saddened by the shooting.”
“The incident was quickly contained by security personnel on site,” the company said, according to WZTV. “The safety of our team members is a top priority for our business and we maintain strict security protocols and a gun-free policy at all of our facilities. We are working with local police as they investigate this matter. “
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