Jamaican police today admitted there was no evidence that Bob Woolmer was murdered.

Lucius Thomas, Jamaican Constabulary Force (JCF) commissioner, confirmed Woolmer had died of a heart attack three months ago and was not poisoned or strangled.

The force launched a murder investigation after a pathologist's report indicated that Woolmer had died as a result of asphyxia due to "manual strangulation". He had been found dead in his hotel room in Jamaica hours after his team had been knocked out of the cricket World Cup by Ireland in a shock defeat.

With the world's media watching the subsequent investigation saw some of the Pakistani cricket team individually questioned and DNA tested.

Speculation followed that the team, or its supporters, could have been involved in the death and that it may have been connected to a betting ring.

Imran Khan, the former Pakistani cricket captain, urged his countrymen to sue the Jamaican police or pathologists, but the chairman of the Pakistan Cricket Board said it was unlikely legal action would follow.

"I don't think there will be any legal ramifications from us. We are very glad the matter is over and it is time to move on now,” said Nasim Ashraf.

Urging legal action, cricketer-turned-politician Mr Khan said: "Pakistan Cricket Board should sue everyone with responsibility because this was so damaging for the Pakistani team, for Pakistan cricket and to the country.

"They should have ruled out first whether this was natural causes. By what Pakistan cricket has been through - players being DNA tested, finger-printed, insinuations of match-fixing, insinuations that the players might have killed their coach - all this was so damaging and this went on for a good two months. And I think someone should be held responsible for it."

Mohammad Yousuf, a star Pakistan batsman, echoed Khan's demands, saying: "The PCB should take legal action. But it’s not up to the players. We cannot sue the Jamaican police. It is a matter to be handled by the PCB.

"It was their investigation. It was okay and we cooperated, but we were fingerprinted and not allowed to leave, which added to our pain of being knocked out of the World Cup."

But the team's then-captain Inzamam-ul-Haq, one of three Pakistan players questioned twice, said legal action would be pointless. "I don’t feel court action would be of any use now. The players in general and I, as captain in particular, went through hell and those were the most terrible days of our lives.

"We must be ready to handle such things better in future by involving the Government and the (Pakistan Cricket) board from the initial stages."

After fresh toxicology tests, Mr Thomas said foreign pathologists "concur with the view that Mr Woolmer died of natural causes. . . no substance was found to indicate that Bob Woolmer was poisoned".

"The JCF accepts these findings and has now closed its investigation into the death of Mr Bob Woolmer," he told journalists.

Sitting alongside him, former Metropolitan Police officer Mark Shields, the deputy Jamaican policing commissioner, said that the force had been obliged to take seriously the initial pathologist's finding that Woolmer was murdered.

He said that it was the force's decision to ask for "second, third and fourth" opinions that had eventually resolved the issue.

"As far as we are concerned, we consider that we provided a thorough and professional investigation."

Mr Shields added that it was not his job to criticise the pathologist, Dr Ere Seshaiah, who gave the initial murder verdict. "It would be for others to mention or talk about Dr Seshaiah at some other time," he said.

In his statement, Mr Thomas tried to calm tensions between the Pakistan cricket team and the Jamaican force by thanking the team for co-operating with the investigation.

Tonight Woolmer's widow, Gill, expressed relief that the investigation was over and she and her family could begin to mourn.

"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 the family's home in South Africa.