Green, whose arrest sparked outrage among opposition politicians, said anti-terror police officers seized a computer from his parliamentary office and searched it using the key words 'Shami Chakrabarti.'
"This feels to me like a fishing expedition on somebody who embarrasses the government of the day," Green told The Times, adding that his arrest and the raids on his office and home smacked of a "police state."
Green, who is his party's spokesman on immigration issues, was arrested after publicising home ministry documents that showed illegal immigrants had been able to secure jobs of security guards and a cleaner in the lower house of parliament.
Chakrabarti, who heads the civil liberties group Liberty, said she was never approached by police as part of their inquiry and was alarmed to learn that her name had been used as a key search word.
"I think this raises very serious questions about just how politicised, even McCarthyite, this operation was," she added, referring to the American anti-communist witch-hunts led by Senator Joseph McCarthy in the 1950s.