Ere Sheshiah, whose original finding in March that Woolmer was strangled launched a far-reaching murder inquiry and sparked feverish speculation that it was related to corruption in international cricket, said he stuck by his findings.
"In my opinion, Woolmer died from asphyxia due to manual strangulation associated with cypermethrin poisoning," said Sheshiah, who said the chemical is used widely in many countries where cotton is grown such as Sri Lanka, India, Bangladesh, and Pakistan.
Woolmer died on March 18, when he was found unconscious in his Jamaican hotel room the day after Pakistan were embarrassed by Ireland in a cricket World Cup upset.
Sheshiah said that cypermethrin can cause symptoms including "salivation, vomiting, diarrhea and muscular incoordination," which may have accounted for the scene of disarray that medical personnel found at Woolmer's room.
Sheshiah, whose procedures in the post mortem have been criticized by three other pathologists asked to review the case, said police pressed him to offer conclusion in the case before he recieved the results of the toxicology report.
The three other pathologists, South African Lorna Martin, Britain's Nathaniel Cary and Canadian Michale Pollanen, have all testified that Woolmer appeared to have died of natural causes, probably related to heart disease.
In June, Jamaican authorities said they were no longer treating Woolmer's death as homicide.
Sheshiah, 65, was expected to testify further on Thursday in the inquest presided over by coroner Patrick Murphy and 11 jurors. The proceedings are expected to continue until early November.