Autopsy of Chicago lottery winner yields no new clues on poisoning

The body of Urooj Khan is carried to a hearse for forensic autopsy by the Cook County Medical Examiners office in Chicago, January 18, 2013.

CHICAGO (Reuters) - A post-exhumation autopsy of a Chicago man who died from cyanide poisoning shortly after winning a $1 million lottery prize yielded no clues in the murder case, authorities said on Friday.

Because of decomposition, there was no trace of cyanide found in the tissues of Urooj Khan, 46, or in his stomach, according to Cook County Medical Examiner Dr. Stephen Cina. Authorities found a lethal level of cyanide in a blood sample soon after his death last summer.

Khan died on July 20 without a will, and his estate is still mired in a legal battle in the probate division of Cook County Circuit Court. A judge on January 11 granted investigators permission to obtain the additional forensic samples.

Investigators could not tell from the post-exhumation autopsy if the cyanide was ingested, injected or inhaled, Cina said.

"Cyanide has a short half-life and may be lost over the postmortem period unless tissues are adequately preserved," Cina told reporters.

Khan's death initially was ruled to be caused by heart disease, and no autopsy was performed. Toxicology results indicated no drugs or carbon monoxide present.

But several days after his body was released for burial, an unidentified family member asked the medical examiner to revisit the case. The medical examiner's office ordered comprehensive toxicological testing of samples already in its possession.

Final test results confirmed in November that there was a lethal level of cyanide in Khan's blood, according to the medical examiner, which ruled his death a homicide.

Cina said on Friday that the autopsy also found severe blockage in one of Khan's major coronary arteries, so coronary artery disease was named a contributing factor in his death.

Chicago police are investigating the death as a murder. No suspects have been named.

Khan presented his winning Illinois state lottery ticket on May 31, and chose a lump-sum payment of about $424,500 after taxes.

Khan's wife, Shabana Ansari, has told reporters the family shared a curry dish she made that night, according to media reports. She also said that she adored Khan and could not imagine why anyone would want to kill him.

(Reporting by Mary Wisniewski; Editing by Cynthia Johnston and Jim Marshall)