An employee crashed his car through a Pillsbury plant's security gate during a shift change Wednesday morning and then fatally shot a co-worker as others watched in horror, authorities said.

The shooting occurred as officers were investigating a report of gunshots outside a home less than a mile away, police said.

Police Capt. Keith Whitlow said neither the suspect nor the victim lived at the home. He declined to comment on a motive for the shootings, saying only that they occurred after an "altercation" at the house.

Floyd County Coroner Leslie Knable, however, told The Tribune that the shooting involved a "love triangle" between a woman who lived at the home, the suspect and the victim, whom police identified as Christopher J. Trowell, 48, of Louisville, Ky.

The suspect, who was arrested outside the plant, is believed to be responsible for both the shooting at the house, where at least one shot was fired into the building, and at the factory just north of Louisville, Whitlow said. No one else was injured.

Tom Forsythe, a spokesman for General Mills Inc., which owns the plant, said the worker who was killed finished his shift Wednesday and left the plant. He then returned for an unknown reason. Forsythe said the gunman had not been scheduled to work Wednesday.

The gunman was being held at the Floyd County Jail on a preliminary charge of murder. Whitlow said police would not release his name until Thursday, when formal charges are expected to be filed.

Several Pillsbury workers saw the shooting at the plant, which occurred near the loading dock around 7 a.m.

"There were all kinds of people coming and going, night shift to day shift making that transition and there was also a lot of deliveries being made, truck drivers in the area," Whitlow said.

While police believe the suspect crashed his car through the plant's security gate, Whitlow said witnesses told officers the victim also had driven a van through the gate before the shooting.

He said investigators planned to interview the witnesses and review the plant's security videotape to see exactly what happened.

The plant employs about 500 people and produces and ships refrigerated dough products such as crescent and cinnamon rolls and cookies. It marked its 50th anniversary on Sunday.

After the shooting, General Mills sent the plant's workers home and temporarily suspended operations so the company could assist police with their investigation.