Khan's body was exhumed Friday from Rosehill Cemetery to allow the Cook County Medical Examiner to perform an autopsy.
Khan died in July, one day after collecting $425,000 for his lottery win. At first, his death was not considered suspicious, but it was reclassified as a homicide after cyanide was found in a blood sample.
Officials say it will take a few weeks for toxicology tests to be completed.