Updated

An autopsy on the exhumed body of a Chicago lottery winner poisoned with cyanide yielded no significant new clues about his death, the Cook County medical examiner said Friday.

No remaining cyanide was found in samples of Urooj Khan's body tissue, likely because cyanide breaks down over time, and there was nothing notable from tests on his stomach contents, Stephen Cina told reporters.

Cina did say Khan's coronary arteries had significant blockage, which could have increased the effectiveness of the cyanide. But he said there was nothing to make him think a heart attack killed Khan, saying, "I don't see how I can ignore lethal cyanide level in the blood."

Authorities have not publicly identified anyone as a suspect in Khan's July 20 death, which happened just days before the 46-year-old was to collect $425,000 in lottery winnings.

Authorities initially ruled that the Indian-born businessman died of natural causes, but his brother raised suspicions, leading authorities to test fluids drawn from Khan's body before he was buried. Those tests showed he had been poisoned, and Khan's body was exhumed in January so that authorities could perform the autopsy and gather more evidence in case prosecutors decide to file charges.

Although the autopsy didn't reveal significant new information, Khan's death is still considered a homicide because definitive tests on fluids drawn from his body before he was buried indicated he had been poisoned, Cina said.

Khan moved to the U.S. from Hyderabad, India, in 1989, and over the years, he set up several dry-cleaning businesses and bought into some real-estate investments.

Despite having foresworn gambling after making the haj pilgrimage to Mecca in 2010, Khan bought a lottery ticket in June. He said winning the lottery meant everything to him and that he planned to use his winnings to pay off mortgages, expand his business and donate to St. Jude's Children's Research Hospital.

The night before he died, Khan ate dinner with his wife, daughter and father-in-law at their house. Sometime that night, Khan awoke feeling ill. He died the next morning at a hospital.

Khan died without a will, opening the door to a court battle. The businessman's widow and siblings fought for months over his estate, including the lottery check.

Khan's wife, Shabana Ansari, and other relatives have denied any role in his death and expressed a desire to learn the truth.

Authorities remain tightlipped about whom they may suspect.

One of Khan's brothers and a Muslim cleric were present at the exhumation at Rosehill Cemetery, along with officials from the medical examiner's office and Chicago police detectives.

After exhuming his body in January, pathologists collected samples of hair, nails and most major body organs, as well as contents of the stomach, Cina said at the time. He had hoped the tests might determine whether Khan swallowed, inhaled or was injected with the poison.

Khan was given a religious burial and his body was not embalmed. The body was wrapped in a shroud and placed inside a wooden box with a Styrofoam lid that was itself inside a concrete vault. Cina has said the body had not come into contact with soil from the grave.

Speaking in January, he said cyanide over the post mortem period can evaporate and leave the tissues.