CHICAGO — With no signs of trauma and nothing to raise suspicions, the sudden death of a Chicago man just as he was about to collect nearly $425,000 in lottery winnings was initially ruled a result of natural causes.
Nearly six months later, authorities have a mystery on their hands after medical examiners, responding to a relative’s pleas, did an expanded screening and determined that Urooj Khan, 46, died shortly after ingesting a lethal dose of cyanide. The finding has triggered a homicide investigation, the Chicago Police Department said Monday.
‘‘It’s pretty unusual,’’ said the Cook County medical examiner, Stephen Cina, commenting on the rarity of cyanide poisonings. ‘‘I’ve had one, maybe two cases out of 4,500 autopsies I’ve done.’’
In June, Khan stopped at a 7-Eleven near his home on the city’s North Side and bought a ticket for an instant lottery game.
‘‘Winning the lottery means everything to me,’’ he said at the June 26 ceremony, also attended by his wife, Shabana Ansari, and their daughter, Jasmeen Khan.
Instead of the full $1 million over installments, Khan opted to take his winnings in a lump sum of just over $600,000. After taxes, the winnings amounted to about $425,000, said lottery spokesman Mike Lang. The check was issued from the state Comptroller’s Office on July 19, the day before Khan died, but was cashed on Aug. 15, Lang said. If a lottery winner dies, the money typically goes to his or her estate, Lang said.