A report into five deaths from the human form of mad cow disease around one English village found local butchers were the most likely cause of the cluster of fatalities.
The inquiry into the deaths in and around Queniborough, central England, was launched last summer in the hope that it would unlock the key to how bovine spongiform encephalopathy (BSE)was passed to humans.
There are 95 confirmed or probable cases of new variant Creutzfeldt-Jakob Disease (vCJD), the devastating condition which leads to the gradual loss of co-ordination and speech and ultimately death.
More than 80 of those have been fatal and two people are also reported to have died in France of vCJD.
"We developed the hypothesis that the people who had developed variant CJD were exposed to the BSE agent through the consumption of beef and carcass meat," said Dr Philip Monk, one of the report's authors.
He specified meat from the butchers in question was at risk of cross-contamination with bovine brain material during the boning, jointing and cutting process in those butchers' premises where the heads of beasts were split to remove brain.
Prof Roy Anderson, epidemiologist at Imperial College in London and an adviser to the inquiry, said butchers around the Leicestershire village had apparently continued to have physical contact with cows' brains despite the fact the practice had become increasingly rare in the 1970s.
It was banned by the government in 1989 - three years after BSE was first identified in Britain.
Prof Anderson warned against reading too much into the report but said it shed some light on the likely incubation period of vCJD.
"It's beginning to put the incubation period in the region of perhaps 10 to 16 years," he said.
Some scientists dismissed the inquiry as a gimmick aimed at finding a scapegoat without addressing the causes of vCJD.
"We don't know the year it started. We don't know how it got from the cows to people. We have no idea as to how it spread in detail from cows to people," said Prof Richard Lacey, one of the first people to link BSE and CJD 10 years ago.
"It's not really being very honest . . . This has been the whole basis of BSE over 15 years - not to get at the truth but to reassure in the short term," he told BBC radio.