Puzzling cliff-hanger in case of poisoned lottery winner

CHICAGO (AP) — With his departure from office this week, a county medical examiner leaves behind a beguiling mystery set in motion more than three years ago with his sensational declaration that a Chicago businessman who had just won a $1 million lottery prize was poisoned by cyanide.

Initially, the medical examiner's office ruled he died of natural causes after an external exam turned up no signs of trauma.

The default cause of death was listed as arterial sclerotic cardiovascular disease, which covers the major natural causes of death, such as a stroke or a heart attack.

According to Cina, who became the chief medical examiner that September, the test came back positive for cyanide.

Khan's body was exhumed in January 2013 for further tests, but by then no cyanide was detectable in the badly decomposed remains, and it was impossible to tell how the lethal dose entered his body, Cina said in a news conference a few weeks later.

A probate settlement split Khan's estate — including the lottery check — between her and her estranged stepmother and barred either side from filing a wrongful death lawsuit against the other unless the police investigation turns up evidence.