CHICAGO (AP) — A Chicago medical examiner says a lottery winner was fatally poisoned with cyanide a day after he collected nearly $425,000.

Cook County Medical Examiner Stephen Cina says a limited exam initially found Urooj Khan died of natural causes, but a relative asked for a deeper investigation.

A full toxicology test revealed Khan had ingested a deadly amount of cyanide, and his death was re-classified as a homicide.

Khan died July 20, a day after collecting the lump sum option on a $1 million win. He bought the ticket at a 7-Eleven near his home in West Rogers Park, a neighborhood on Chicago’s North Side.

Cina said Monday it’s likely that Khan’s body will be exhumed as part of the investigation into his death.