Stanley Adams, the man who exposed illegal price fixing by the Hoffman-La Roche drugs company, told Bristol Crown Court that he and his wife, Deborah, had been in dispute with her brother and sister-in-law over an inheritance.
Mrs Adams had been cut out of her parents' will when she married him and the couple were trying to persuade her brother, Charles Shepherd, to sign a document promising them pounds 150,000. Mr Adams blamed his refusal on the influence of his wife, Jennifer.
He said he contacted Tony Cox, a former soldier, because he wanted to frighten Mrs Shepherd as an act of revenge. He added: 'In my opinion she was the one hindering Deborah's rightful inheritance.'
Mr Adams, 66, of Chilthorne Domer, near Yeovil, Somerset, denies soliciting Mr Cox to murder his wife. He was arrested last year after a meeting with Mr Cox who had told police about the plan.
The prosecution claims Mr Adams wanted Mr Cox to kill his wife so that he could claim pounds 500,000 life insurance. He had doubled the sum payable on her death without telling her about most of the policies.
Mr Adams told the court he wanted to find someone who would frighten Mrs Shepherd, but denied planning to have her killed, kidnapped or beaten up. He said he decided to abandon the plan, but did not tell Mr Cox because he was scared he might shoot him.
The case continues.