Updated 01/07/13 - 4:43 p.m.
CHICAGO (CBS) -- Investigators have been trying to determine how a 46-year-old man who won $1 million on an instant lottery game last summer ended up dying from cyanide poisoning.
CBS 2's Derrick Blakley reports Urooj Khan won a $1 million jackpot in a scratch-off game in June, after buying a ticket at a 7-Eleven in Rogers Park.
He repeatedly jumped for joy, and shouted "I hit a million!" but just days later he was dead.
The Cook County Medical Examiner's office performed a visual exam after Khan's death, but did not conduct an autopsy, ruling his death to be the result of natural causes.
"He did not have any obvious trauma. The initial investigation didn't suggest anything suspicious about his death," Cook County Medical Examiner Dr. Stephen Cina said Monday.
But days after Khan died at St. Francis Hospital in Evanston, a relative called the medical examiner's office, saying something didn't add up.
"They just felt this didn't seem likely, that it didn't seem like it could have been a natural to them, and they just wanted us to look a little harder," he said. "In forensics, you have to have an open mind, and when additional information comes to light, you have to be willing to revisit cases."
So a new autopsy was ordered, and toxicology tests revealed a new cause of death: homicide by cyanide.
"Life's not like CSI. Sometimes there's not a smoking gun that leads us immediately toward the perfect conclusion," Cina said.
Khan lived an immigrant's dream. Arriving from India with nothing, he owned several dry cleaners and rental property.
At Khan's shop on Western Avenue, his widow said she could write a book about how great her husband was, but she didn't want to talk on camera.
Khan was buried at Rosehill Cemetery, but the next step in the investigation could be exhuming his body.
"I've been in discussions with the Chicago Police Department, and with the [Cook County] State's Attorney's office, and it looks like we're leaning in that direction," Cina said.
Exhuming Khan's body could produce more detailed toxicology information. Death by poisoning of any type is extremely rare. Of the 508 Chicagoans murdered last year, Khan was the only one who was poisoned.
Cina said, of the 4,400 autopsies he's performed in his career, he's had only one poisoning.
He said poisoning is so rare, he wrote about the case in a medical journal.
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