* Novartis CEO a target for escalating attacks
* Animal rights group says it behind arson attack
* "We will attack your private life" - group says
* British testing laboratory Huntington in spotlight again (Adds claim of responsibility for arson attack)
ZURICH, Aug 6 (Reuters) - Animal rights activists claimed responsibility on Thursday for burning down the holiday home of Novartis (NOVN.VX) Chief Executive Daniel Vasella as Swiss police said a second grave of his family had been desecrated.
Vandals sprayed a Vasella family gravestone with the slogan "Drop HLS Now", police said, a reference to the British animal-testing laboratory Huntingdon Life Sciences (HLS) that has been a major target for protests by animal rights activists.
They also stuck two wooden crosses in the ground, the spokesman said. He declined to confirm Swiss media reports the crosses carried the names of the Novartis CEO and his wife.
Vasella's Austrian holiday home caught fire on Monday and the Austrian interior ministry said they had receved a claim of responsibility from a group called Militant Forces Against Huntingdon Life Science and its authenticity was under review.
In a statement posted on a direct action website, the group said they had petrol bombed Vasella's hunting lodge. "Understand this: this will continue until you sever all ties with Huntingdon Life Sciences. We will attack your private life wherever possible," the statement said.
The cemetery attacked last week was the same where Vasella's parents' grave was desecrated and an urn containing the ashes of his mother stolen.
Police also found the letters 'SHAC' -- the acronym for the Stop Huntingdon Animal Cruelty group that campaigns to close down the centre -- sprayed in paint. Swiss police are examining the evidence but have no suspects so far, the spokesman said.
SHAC denied involvement in the attacks but said some like-minded person might have been behind them and vowed to continue its campaign against firms it said were Huntingdon customers like Novartis, AstraZeneca (AZN.L), Bristol-Myers Squibb (BMY.N) and GlaxoSmithKline Plc (GSK.L).
REVIVAL OF MILITANT ACTIVISM?
The Swiss drug maker said it no longer uses Huntingdon but suspects SHAC or those linked to it are behind the attacks.
"We see this as an escalation. There have been more and more of these types of incident and attacks," a Novartis spokesman said. "From the tactics as well as the signs that were left, the feeling is it is probably related to SHAC."
Other recent incidents include graffiti sprayed in Vasella's street saying "Vasella is a killer. We are watching you." Employees' cars have being damaged and there was a fire at a Novartis sports facility in France in May, the spokesman said.
The attacks on Novartis may mark a revival of animal rights activism in Europe, which reached a peak in Britain before the introduction of new police powers five years ago.
Much of the action was focused on HLS, a contracting firm in eastern England which uses animals to test the safety of drugs, food additives and chemicals. In 2001, its chief operating officer was attacked by protesters wielding baseball bats.
Many pharmaceuticals manufacturers have also been targeted over the years and sporadic action has spread to the United States and other parts of Europe, leading to fears investment in drug research and development could be jeopardised.
A spokeswoman for Switzerland's other big drugmaker Roche Holding AG (ROG.VX) said it had not been attacked in recent years, but Europe's biggest biotech company, Actelion (ATLN.VX), said the property of several of its workers had been vandalised.
"It has long been a concern of ours that animal extremists would broaden their scope beyond the UK to what they might see as softer targets," said Richard Ley, a spokesman for the Association of the British Pharmaceuticals Industry.
According to the British Union for the Abolition of Vivisection, some 12 million animals are used annually in experiments in Europe.
The drugs industry says it is exploring alternatives but that animals remain a vital part of the research and development of new medicines and vaccines. The vast majority of animals used in medical experiments are mice.
(Additional reporting by Paul Arnold in Zurich, Alexandra Zawadil in Vienna and Ben Hirschler in London; editing by John Stonestreet and David Cowell)