Authorities are struggling to determine with certainty what killed Matthew Lebold, an apparent drug user who was also missing large portions of his face when his body was found.
Police were called to the 25-year-old Lebold's home in the Lakeview neighborhood of Chicago on Tuesday afternoon for a well-being check. His father made the call after not hearing from him for some time, according to the Chicago Tribune.
He was found dead in the home, appearing to have overdosed on drugs -- but also having suffered serious trauma to his upper body from his pit bull.
A source told the Chicago Sun-Times that the dog "had eaten through parts of the man’s face, neck and chest after he was dead."
At first, it was unclear if the dog had killed Lebold, but after further analysis, investigators believe the wounds were inflicted postmortem.
The autopsy performed on Lebold Wednesday was inconclusive, but the Cook County Medical Examiner's office is still waiting on results from a toxicology test, which will likely confirm that his death was drug-related.