Four animal rights activists face prison sentences after being found guilty of orchestrating a blackmail and terror campaign intended to close down the Huntingdon Life Sciences (HLS) testing centre in Cambridgeshire.
The two men and two women, part of an extreme direct action protest group, targeted firms linked to the Huntingdon laboratories by falsely accusing company directors of being paedophiles, threatening to infect them with HIV-infected needles and carrying out bomb hoaxes at their businesses.
Other tactics used to try to force the companies to cut their links with the centre included sending used sanitary items in the post and daubing roads outside managers' homes with insults such as "puppy killer".
Heather Nicholson, 41, of Eversley, Hampshire; Gerrah Selby, 20, of Chiswick, London; Daniel Wadham, 21, of Bromley, south London, and Gavin Medd-Hall, 45, of Croydon, south London, were all found guilty at Winchester Crown Court of conspiracy to blackmail.
Another defendant, Trevor Holmes, 51, from Newcastle, was cleared by the jury after seven days of deliberation.
Earlier, three other people, Gregg Avery and Natasha Avery, both of Hampshire, and Daniel Amos, of no fixed address, pleaded guilty to conspiracy to blackmail.
The jury was told that the defendants were all were members of the Stop Huntingdon Animal Cruelty (Shac), which was based near Hook, Hampshire, and had embarked on "military precision" campaigns to target companies in the UK and Europe between 2001 and 2007. Margaret McQuillan, a PA at a company called Astellas, was targeted and had her house and car daubed with paint saying "ALF" (Animal Liberation Front) and "puppy killer".
The scientist Christopher Bevan, who worked for GlaxoSmithKline, was targeted in a similar way, and Keith Goodchild, who worked for Novartis, had letters sent to his neighbours falsely claiming he was a serial sex offender who went abroad to abuse children. William Denison, managing director of F2 Chemicals, said his family's life was turned into a "living hell" for six months when he was targeted by Shac. He said a hoax bomb was sent to his home and letters alleging that he was a paedophile were sent to up to 200 families in his village near Preston, Lancashire.
Mr Denison said it could have had a massive impact on his family because his wife worked as a children's special needs assistant and he helped create floats for local children's events.
Fourteen slogans, including "Bill the murderer" and "Bill the ALF [Animal Liberation Front] are coming for you" were painted in red on a 500-yard stretch of road near his home.
F2 Chemicals did not deal directly with HLS but supplied a Japanese glass company which had closer links.
Mr Denison said that unpaid-for items such as CDs and clothing, including a size 44E bra for his "slender" wife, were sent in an attempt to give him a bad credit rating.
Vincent Howard, operations director for the distribution company Biocair in Cambridge, was also targeted, even though his company did not deal directly with HLS but only for firms which had links with it.
He said the campaign of intimidation began with protests outside his company's offices before the extremists started targeting his family home.
They poured paint-stripper over his car and punctured its tyres. Then, like in Mr Denison's case, a letter was sent to 30 people in his village falsely stating he was a convicted paedophile.
The campaign was brought to an abrupt halt by a massive police raid involving 700 officers targeting addresses across the UK, the Netherlands and Belgium in May last year. All seven will be sentenced on 19 January.