Police on Friday identified the four people killed in a shooting at a St. Louis industrial plant and confirmed that man suspected of opening fire was among the dead.

Suspect Timothy Hendron, 51, of Webster Groves, Mo., died of a self-inflicted gunshot wound beneath his chin, police said. He was found inside ABB Inc.'s plant on Thursday.

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Police believe Hendron shot and killed three of his co-workers at the sprawling plant: Cory Wilson, 27, of Collinsville, Ill.; Terry Mabry, 55, of Moscow Mills, Mo.; and Carlton Carter, 57, of St. Louis. All three were shot in the head. Mabry was also shot in the leg and Wilson in the shoulder.

Five other people were wounded, all of them men in their 50s. Two were in critical condition, two were in fair condition and one was treated at a hospital and released.

The shootings began at 6:30 a.m. Thursday, sending the 40 to 50 employees inside the building scurrying to the rooftop, broom closets and boiler rooms to seek safety. Police said Hendron was armed with an assault rifle, shotgun and handgun.

The motive wasn't known. But in 2006, Hendron and other ABB workers sued the company over retirement losses. The federal lawsuit accused ABB and its pension-review committee of causing their 401(k) accounts to include investment options with "unreasonable and excessive" — and undisclosed — fees and expenses. The trial began Tuesday in Kansas City.

The shooting occurred during a shift change at the plant, which employs about 270 people. Forty to 50 employees were likely in the building at the time, police Capt. Sam Dotson said.

Police said the bodies of Carter and Mabry were found outside the building. The bodies of Wilson and Hendron were inside. All four were pronounced dead at the scene.

Swiss-based ABB Group makes power transmission and industrial automation equipment. It manufactures transformers at the St. Louis site.

Wilson was a supervisor at the plant, according to Carl Poelker, a football coach at McKendree University in Illinois, where Wilson was an all-conference linebacker. Wilson played in high school at Collinsville and was an assistant coach there.

"I never saw the kid have a bad day," said Poelker, whose oldest son, Tim, was a close friend of Wilson's and had been out with him the night before the shooting. "It was always life is good, life is wonderful. And he played football like that — on a Saturday afternoon, he thought it was just great to go out there, and it permeated with the rest of the team."

Poelker said the shooting left many people at McKendree and in Collinsville struggling.

"It's just so senseless," he said. "It's not only the coaches here, but there are a lot of people with a big hole in their stomach now. So many people liked him and considered him a friend."

Many of Hendron's neighbors in Webster Groves, a St. Louis suburb, described him as an amicable family man. Yet even those who knew him casually were aware that Hendron was unhappy at work. He mentioned in passing that he was having problems at ABB, and over the last two years he asked his neighbor Mike Sweney, an attorney, for referral to a good labor lawyer.

"I sensed a certain disgruntlement on his part," Sweney said.

Jerry Schlichter of the St. Louis-based Schlichter, Bogard and Denton law firm, which is representing Hendron and the other ABB workers in their lawsuit, declined to discuss his client Thursday during a break in the trial.

Police searched Hendron's modest, brick home in the middle-class neighborhood. Neighbors said Hendron left behind a wife and teenage son.

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