Investigations into the foot and mouth outbreak in Britain points the finger of suspicion for the source of the infection to the nearby research centres.
Following reports of a confirmed third case, initial investigations appear to have however failed to pinpoint which of two organisations, which share the same site south of London, is the culprit, the state-funded Institute for Animal Health (IAH) or the animal pharmaceutical company Merial.
The outbreaks are fuelling fears of a repeat of the devastating 2001 epidemic.
The Health and Safety Executive's interim findings say there was a "strong probability" that the leaked strain came from one of the two, and it was highly likely that the disease was spread by human movement.
Any idea that the virus could have been carried in floodwater has been ruled out.
To date around 200 animals have been slaughtered but farmers across the country fear the virus may have spread further following the suspected leak.
The Pirbright research centres for the IAH and Merial were set up 1997 after a merger involving divisions of American drug giant Merck and French firm Rhone Merieux.
The research centers are five kilometres from the farm where foot and mouth was initially confirmed last Friday and the herd in the second outbreak was grazing nearby.
Both laboratories conduct research and develop vaccines against foot and mouth, and handle the exact, rare strain of the virus that struck the herd, a strain isolated by British scientists 40 years ago.
The disease strain found at the first infected farm was being used at both the IAH and Merial in the second half of July, though the quantities handled by each organisation were significantly different.