Why aren't journalists helping Mahar Arar?

The Globe features a story today on the government's continued search for RCMP officials who leaked false information to the press about Mahar Arar. Colour me confused, because I don't understand why journalists who were lied to just don't give up their sources. I have all the respect in the world for people like Juliet O'Neill, who stood up for her journalistic rights in the face of an illegal RCMP raid. But now, given that she's been lied to, why doesn't she reveal who deceived her? And why not all the other journalists who received false tips? If they believe the Arar case is a tragedy, then they should square up to their role in its furthering.