Animal rights activists have claimed responsibility for an attack on the London home of a senior manager with pharmaceutical giant, GlaxoSmithKline.
GlaxoSmithKline says it is reducing the number of animals in research
Large white letters were daubed across the garage door of solicitor Simon Bicknell's home on 19 January.
Animal Liberation Front (ALF) said it was behind the attack and threatened to return unless he resigned from his role as company secretary.
A spokesman for the firm said security for its executives had been stepped up.
In a website message, activists said Mr Bicknell, 46, should leave his "sick and amoral job", otherwise they would return.
Robin Webb, spokesman for the ALF, described the company as a "legitimate target" because of its animal testing work, and said the intention was to cause economic disruption.
"Why should those responsible for the pain and suffering of animals be allowed to go home and relax when animals are in those conditions 24 hours a day?"
But a GlaxoSmithKline spokesman defended animal testing, saying: "We have to test on animals before we test on humans, but we are working to reduce the number of animals in research.
"But there are certain things we just cannot do in a test tube or with a computer and legally we are obliged to do these tests."
A police investigation is under way, but so far no-one has been arrested.
Last September, another GlaxoSmithKline employee came under attack when an explosive device was left outside executive Paul Blackburn's home causing minor damage.