The Cook County Medical Examiner's Office is making the request.
Urooj Kahn died one day after collecting a lotto check for $425,000. His death was reclassified a homicide after the cyanide discovery.
His wife Shabana Ansari told ABC 7 that his body should be exhumed from Rosehill Cemetery.
"I support it," Ansari said. "The way things are going now God is going to reveal the truth."
Four people ate what turned out to be Khan's last meal in July, according to Ansari. The meal at the family's Roger's Park home included Khan, his teenage daughter, Ansari and her father Fareedun Ansari, who lives with the family.
"We ate together," she said. "All four of us had the same meal that day."
Ansari's attorney said she had nothing to do with her husband's death.
Fareedun Ansari has two federal tax liens against him. One is for $93,000 and the other is for more than $31,000. The elder Ansari, who was at the family's dry cleaning business Thursday, declined to comment about the liens.
The lottery money, as well as Khan's other assets, are part of an on-going probate case between his widow and his brother.
His brother, through court documents, says he wants to make sure Khan's teenage daughter from a previous marriage get her share of the assets.