A man who won the Illinois lottery was killed by cyanide poisoning, an autopsy revealed, and now his body will be exhumed in an effort to gain some clue as to how it happened.

Death by cyanide poisoning is extremely rare, officials say, and usually occurs over an extended amount of time. Urooj Khan was issued his lotto check for $425,000 and died mysteriously the next day, after his family heard him screaming in the night from his bed. He was taken to the hospital, where he passed away.

“We are investigating it as a murder, and we’re working closely with the medical examiner’s office,” Chicago police spokeswoman Melissa Stratton said.

Now, the question is not only who did it, but how they came across enough of a dose to be fatal. Unless the murderer was able to obtain it from an industrial cleaner somehow, officials say the source could prove puzzling. Certain foods hold tiny amounts of the poison, but a person would have to ingest a very large amount to become sick. Also, the victim would exhibit telltale signs of illness, such as weakness, dizziness, vomiting, headaches, and seizures.

Unfortunately, cyanide breaks down in the body quickly, and Khan has already been embalmed and buried. However, tests can be run on his organs to determine whether he ingested the poison, inhaled it, or was injected with it, which could be extremely helpful. Authorities say they will do what they can to reveal any clues concerning his death, and are actively pursuing the case as a murder investigation.

Image: Illinois Lottery