Portage, WI – Duluth News Tribune – A man whose body was found in an unventilated camper died accidentally from carbon monoxide poisoning and may have been dead for up to three months, authorities said Wednesday.

Donald A. Czyzewski, 51, of Cicero, Ill., was found Monday in the camper on land he owned in the Town of Caledonia, Columbia County Coroner Marc Playman said in a statement.

Czyzewski was using a liquid petroleum heater in his small unventilated camper, Playman said.

Foul play was ruled out.

Czyzewski’s 76-year-old mother Lucille said she got a postcard from her son in January after waiting for him to come home to Cicero for Thanksgiving and Christmas.

“It must of been in January that he sent a card saying he’d visit us in February. But he never came – and we waited and waited,” she told The Associated Press in a telephone interview Wednesday night.

She said her son traveled frequently between Cicero and his property in Wisconsin because he enjoyed the area’s forests and lakes.

Wisconsin authorities found Czyzewski’s body after an acquaintance called police to say that he hadn’t seen Czyzewski in several weeks and that mail was piling up in Czyzewski’s mailbox.

A deputy responded to the property and found Czyzewski dead in his camper.