Authorities identified the body as 39-year-old Robert Kruczkowski, of Milwaukee.
The Milwaukee County Medical Examiner's Office earlier said that an autopsy did not show any evidence of injury, but the cause of death is pending further analysis.
Authorities say the body was found in a wooded area on Dec. 7. Three youths came upon it and alerted an adult, who contacted police.
Police say the death remains under investigation.