Authorities reached their conclusion after obtaining opinions from three independent pathologists from Britain, South Africa and Canada and reviewing a toxicology report, Commissioner Lucius Thomas told a packed news conference in the Jamaican capital.

Woolmer, 58, was found unconscious on March 18 in his hotel room in Kingston a day after his team was eliminated from the World Cup in a humiliating loss to Ireland. Authorities first said a preliminary autopsy was inconclusive, but on March 22 announced Woolmer had been strangled, setting off one of the biggest murder investigations in this country's history.

Police questioned nearly 400 people and took DNA samples and fingerprints Pakistan team players and officials before allowing them to depart this Caribbean island. Police also took samples from potential witnesses and other World Cup cricket squads.

There was a flurry of speculation fed by media outlets around the world that match-fixers or an irate fan may have murdered the popular coach. A British TV news show said Woolmer had been poisoned before being strangled, but this was also dismissed by Thomas.

"No substance was found to indicate that Bob Woolmer was poisoned," Thomas said.

Thomas told reporters on Tuesday that a British pathologist reviewed the Jamaican coroner's report saying Woolmer had been strangled and came to the opposite conclusion, finding that he died from unspecified natural causes. The initial autopsy said a bone had been broken in the coach's neck, but Deputy Police Commissioner Mark Shields said Tuesday the other pathologists determined that was false.

"The Jamaican Constabulary Force accepts these findings and has now closed its investigation into the death of Mr. Bob Woolmer," Thomas said.

The coach's widow, Gill Woolmer, welcomed the announcement and thanked Jamaican police.

"My sons and I are relieved to be officially informed that Bob died of natural causes and that no foul play is suspected in his death," she said in a statement from their home in Cape Town, South Africa. "We hope that this matter will now be closed and that our family will be left to grieve in peace."

Shields, a former Scotland Yard detective who led the homicide investigation, said he would not resign over the matter and would serve out the remaining two years of his contract with the Jamaican police.

"I enjoy my job immensely," Shields said.