OSCEOLA — Metro Homicide detectives are investigating the death of an Osceola man, and we now know what killed him.

Autopsy results show 43-year-old Eugene Nusbaum died from a gunshot wound to the chest.

It all started in the parking lot of Schneider’s Auto Sales, in the 1500 block of Lincoln Way West in Osceola. It's where police say an off-duty officer tried to stop Eugene Nusbaum from stealing a catalytic converter out of a minivan.

It happened just feet from Bruce Reidenbach's front door.

"I had my window open, and my wife said, ‘That sounded like gunfire,’” he recalled. “I said, ‘Gunfire?’ And the next thing we heard is just a bunch of loud crashing and booming.”

At 11 p.m. Monday, an off-duty Mishawaka police officer was headed home when, according to police, he noticed Nusbaum in the middle of cutting a catalytic converter from a minivan in that used car lot. The metal is considered valuable as scrap.

The officer approached Nusbaum and told him to stop. Nusbaum climbed into his pickup truck to take off. The officer got between the open door and the truck and even grabbed the gear-shift. But the suspect drove away, dragging the officer, who pulled out his gun and fired several shots. Nusbaum got about a hundred feet down the road before his truck hit a tree head-on and flipped.

Nusbaum had been in and out of the St. Joseph County jail 12 times since 1995, most recently in 2005 for theft.

By Tuesday, all that remained at the crash scene were pieces of a pickup truck, and a damaged tree trunk — fresh reminders of a tragedy that didn't have to happen.

“Just for scrap — that’s a shame,” Reidenbach said.

The officer involved was hurt during the scuffle; but police say his injuries are minor. Authorities have not yet released his name.