Mount Vernon, Mo. ? Authorities are trying to unravel the mystery surrounding a set of human bones found on the floor of an abandoned home in northeast Lawrence County, authorities said Thursday.

Officers with the Lawrence County Sheriff’s Department suspected the bones had been in the home “a few years,” according to a media release. The cause of death was unknown, as was the age, sex and height of the deceased.

An older man who began tearing down the home more than a year ago to recover the lumber discovered the bones loose and mixed in with straw. The man placed the bones in a box, tossed the box in his truck and continued his work, said Richard Reed, 71, of rural Lawrence County, who owns the property on which the house was located.

Several weeks later, the man showed the bones to his neighbor because the man suspected the bones might be more than just animal remains. The neighbor asked his daughter, a pathologist, to examine the bones. She confirmed the bones were human, said Reed.

On Wednesday, the man brought 23 bones to the Sheriff’s Department. Officers returned to the foundation of the demolished home and recovered another 41 items, most of which appeared to be human bones.

A more thorough examination of the bones could take several days or weeks.

Reed, who learned of the bones’ discovery Wednesday, said it had been at least 10 years since the house was occupied.

“It’s really peaked our curiosity, that’s for sure,” Reed said. “It kind of makes you wonder what happened to this person.”