CALUMET COUNTY, WI (WTAQ) -  A woman found dead in an ice shanty on Lake Winnebago this Saturday died of carbon monoxide poisoning. 

That is the findings from the Fond du Lac County Medical Examiner. 

The woman was identified as 31-year-old Sara Meyer of Chilton. 

Meyer along with 37-year-old Travis Duchow were found unresponsive about a half-mile off Ecker Lakeland Drive around 4 p.m. Saturday. 

Duchow was hospitalized and released. 

The cause of the CO poisoning is unknown, but authorities are warning fishermen to use caution when heating their shanties.