Based on autopsy results "the matter of Mr. Robert Woolmer's death is now being treated by the Jamaica Police as a case of murder," police spokeman Karl Angell told a news conference late Thursday, adding the official post-mortem report showed "death was due to asphyxia as a result of manual strangulation."
Woolmer, 58, a former England Test batsman and South Africa coach, was declared dead in hospital on Sunday after being found unconscious in his room at the Jamaica Pegasus hotel.
The day before, Pakistan was knocked out of the World Cup following a shocking defeat by minnows Ireland.
"I don't want to talk about suspects at this stage," Deputy Commissioner of Police Mark Shields said, but he indicated more than one person might have been involved.
"It would take some force, because Bob was a large man, and therefore it would have taken some significant force to subdue him and cause strangulation, but we do not know at this stage how many people were in the room," he said. "It could be one or more people that were involve in this murder."
He also said the person or persons could have entered the room before Woolmer as "the room was undisturbed and all his belongings were intact."
Asked if it was not a regulation of the International Cricket Council that two police officers were placed on the floors of the teams, Shields said: "They are a part of the murder investigation, so I can't comment on that now."
Assistant Commissioner of Police Owen Ellington, chairman of the local security committee, said security arrangements at Woolmer's hotel would be probed.
While it was disclosed that since Woolmer's death officials have increased uniformed security personnel at the hotel, Ellington said it would be inappropriate to reveal further details of security arrangements.
Reading a release on behalf of Commissioner of Police Louis Thomas, Agnell urged anyone with information on the case to come forward.
"It is our belief that those who are associated with or having access to Mr. Woolmer may have vital information that would have assisted this enquiry," he said. "We appeal to those individuals to come forward now and assist us with our investigation."
Shields said he didn't know when Woolmer's body would be flown to his home in South Africa for burial.
"It depends on the coroner whether or not we can release the body," said Shields, adding he would meet with the coroner on Friday. "I think we should be able to do that, but ultimately that is not my decision."
Shields said authorities are still awaiting the reports of the histology and toxicology tests.
Thursday's official statements followed reports in two Jamaican newspapers on the cause of Woolmer's death.
The Jamaica Gleaner quoted a "high-ranking police officer" as saying authorities had suspected strangulation because "a bone in the neck, near the glands, was broken, and this suggests that somebody might have put some pressure on it."
Malcolm Speed, chief executive of the International Cricket Council (ICC), said the entire cricket community was shocked by the circumstances of Woolmer's death.
"When we first learnt of Bob's death a wave of sadness washed over the whole of the cricket community," Speed said in a statement. "That sadness has now been replaced with a profound sense of shock at the news that his death is being treated as murder, and everyone connected with this event will assist the police in any way possible to ensure the truth emerges."
Pakistan's World Cup players gave statements to Jamaican police and were also fingerprinted before leaving for the resort of Montego Bay. They were to stay there for two days before returning home after their early elimination from the tournament.
However, the Pakistan team were furious that they were being cast in some sections of the media as prime suspects in the investigation.
"The impression is being given that the Pakistan team are suspects. This is not true," said team manager Talat Ali.
"It was a matter of ruling nothing out," Shields said. "The Pakistan team is extremely helpful and cooperative."
He added that he saw no reason the team couldn't travel back to Pakistan as scheduled.
"There is no reason why anyone would be detained or stopped from leaving the country," he said.
Before police confirmed the cause of death, rumors swirled of possible poisoning, and even killing at the hands of members of the criminal underworld keen to avoid exposure in allegations of match-fixing which may have arisen in a book that Woolmer was planning to write.
Team spokesman Pervez Mir dismissed the suggestions the death was linked to match-fixing as "totally baseless and premature".