GARRARD COUNTY, Ky. (WKYT) - A death investigation is underway in Garrard County after a missing man's body was found in a storage shed.

Family members found 41-year-old Christian Robinette's body Tuesday in his truck that was parked in a storage garage along Highway 52 just outside of Lancaster.

The Garrard County Coroner says there were no clear signs of what caused the death. He says following an autopsy, the state medical examiners believe he may have died from carbon monoxide poisoning. They think he may have been running his truck inside the shed to keep warm. They keys were not in his ignition when his body was found.

The sheriff's office tell us Robinette was last seen Thursday night leaving his house after an argument with his girlfriend of 20 years. We're told his family looked for him for days, but where unable to find him.

"When nobody could reach him I knew something was wrong," explained Kyle Robinette, the victim's son.

The sheriff says the owner of the storage facility unlocked the shed Tuesday night for Robinette's son who found his father dead.

"I walked around to the other side of the truck and I saw him lying there," explained Kyle Robinette.

The coroner does not believe the death was a suicide.