Updated

Three people were killed early Friday at a lumber company in central North Carolina when an employee shot four of his co-workers before critically wounding himself, WRAL-TV reported.

The maniac began firing at colleagues with a 12-gauge shotgun after arriving at the McBride Lumber Company in Star, roughly 50 miles south of Greensboro.

Three workers died in the rampage while a fourth was in critical condition Friday afternoon after being airlifted to the hospital, Montgomery County Sheriff Dempsey Owens said

WRAL identified the shooter as Ronald Dean Davis, 50. The names of the victims have not been released but Owens said one was Davis' cousin.

After the shooting, deputies found the gunman at his home with a self-inflicted gunshot wound to the head. He was also airlifted to the hospital, where he was in critical condition Friday afternoon.

Owens said Davis, who had worked at McBride Lumber for about a decade, entered the warehouse just after 6:00am local time and started shooting.

He said the victims, among 16 people working at the time, were selected deliberately. "He knew who he went after," Owens said.

Authorities found a rambling six-page letter at Davis' house, which is under investigation. Owens noted that Davis did not have a criminal record.

"It's a very quiet community," Owens said, according to WFMY-TV. "Everybody knows everybody and I don't know what would send a man off the edge to go and do such a heinous act this morning."