Former Pakistan captain Imran Khan on Wednesday described Bob Woolmer's death as a big tragedy but said he did not believe the national coach was murdered.

"I still believe he died of natural causes ... What could be the motives for killing Bob Woolmer?" Khan told Reuters.

Imran, who led Pakistan to the 1992 World Cup title, added: "Until I have any concrete proof, I wouldn't believe even for a one minute that there could be any motive for killing Bob Woolmer."

Imran's comments came after Jamaican police said on Tuesday they were treating Woolmer's death as "suspicious".

One of the top coaches in the world, Woolmer, 58, was found unconscious in his Kingston hotel room on Sunday less than 24 hours after Pakistani team's World Cup defeat by debutants Ireland and pronounced dead in hospital later that day.

Reports from the Pakistan camp at the time said that Woolmer was discovered by hotel staff lying on the floor in his room at the Pegasus Hotel with his mouth wide open.

Blood was discovered on the bathroom floor, there was vomit on the walls and signs of diarrhoea.

Former Pakistan team selector Salahuddin Sallu said it was premature to speculate on the cause of Woolmer's death but emergence of suspicions after Pakistan's humiliating defeat was not unexpected.

"In such circumstances, suspicions do arise. If strong teams lose to minnows, then everybody suspects that there may be some wrongdoing."

Sallu said that if suspicions proved true, then Woolmer's death could become a "major issue for all concerned".