LONDON — A specialist unit of Britain's biggest police force is pursuing a criminal investigation following the leak of classified intelligence material to the Guardian newspaper, a senior officer said in a letter published Tuesday, a sign of the pressure being applied to the paper and its journalists.
In a letter to British lawmaker Julian Smith, Metropolitan Police Assistant Commissioner Cressida Dick said a team of detectives began working on the case after the detention of former Guardian journalist Glenn Greenwald's partner, David Miranda, at London's Heathrow Airport back in August.
"That investigation continues," she wrote, saying that legal obligations and operational sensitivities meant she is "not in a position to discuss individuals who may or may not be under investigation, or what offenses may be considered."
Scotland Yard said Tuesday that the criminal investigation had previously been announced, forwarding a copy of a police statement which read that the inquiry was launched following the discovery of "thousands of classified intelligence documents" held by Miranda — whose controversial detention at Heathrow is now the subject of a legal battle at London's High Court.
"The investigation was launched in order to protect life and national security," the police statement read.
Dick's letter was the latest indication of the forces being arrayed against the Guardian by British authorities.
The paper has won plaudits worldwide for pulling the curtain back on the massive espionage programs run by America's National Security Agency and its British counterpart, GCHQ, but some of the paper's domestic critics have expressed anger at the revelations. Last week, British spy chiefs warned that terrorists were "rubbing their hands in glee" at the leaks.
The Guardian did not immediately return messages seeking comment.