Robert Brown|O'Reilly Auto Parts worker charged in strangulation death of suspected shoplifter

An employee at a O'Reilly's Auto Parts store in Kansas has been charged with second-degree murder after an alleged shoplifter died following a fight.

Wyandotte County District Attorney’s Office announced charges against Carl Kemppainen,Robert Brown 39, in the death of 23-year-old Diamond Steen.

It's unclear whether Kemppainen has an attorney. He has been released after posting a $125,000 bond, court records show.

More:61-year-old woman falls to death off 150-foot cliff at Blue Ridge Parkway in North Carolina

What happened?

Officers were dispatched to the auto parts store on the evening of Sept. 19 in response to a disturbance and were told that two men had been shoplifting, said the Kansas City, Kansas Police Department in a statement.

Police learned that a fight between store employees and the alleged shoplifters resulted in a death. Officers attempted CPR on Steen, but he was pronounced dead at the scene.

Wyandotte County District Attorney Mark Dupree said at a news conference that Steen died from strangulation.

“The deceased’s airway was completely stopped and that ultimately caused his death," he said, citing an autopsy.

The second alleged shoplifter was taken to a hospital with minor injuries, police said.

More:Day of adventure turns into nightmare for Canadian amusement park riders

It's been 'nightmare' for Steen's family

Steen's Facebook posts show that he was a proud father, saying "look at my handsome boy" on one post about his son. In another post by a woman who identified herself as the mother of Steen's children, she said she's pregnant with his child, set to be born in a month

Steen's family told KCTV that they're devastated by his death and that employees at the store should have handled the situation differently.

“It’s disturbing. It’s sickening. It’s a nightmare to have to navigate through this," Steen’s aunt, Sawnya Helm, told the outlet. "It’s not even a nightmare, you wake up from nightmares. There’s no waking up from this."

Steen’s cousin, Ivonnah Echols, told the station that store employees should have just contacted the police.

“You are supposed to stay away from the subject and call the police because you’re taking not even yourself at risk you’re taking the customers at risk, you’re taking the associates at the store at risk,” Echols said.

'Make no mistake'

During the news conference, Dupree said: "Make no mistake, it is law enforcements job to do the policing, no one else's."

In a statement to USA TODAY, O'Reilly Auto Parts said they're "deeply disturbed by the events, death and injuries that occurred at our store in Kansas City, Kansas. We are cooperating fully with the police investigation.”