Channel 4 News presenter Jon Snow has helped police with their "cash for honours" inquiries.
Police are interested in information revealed by Snow in a Channel 4 documentary about the honours system.
Snow told Press Gazette: "I made a documentary about 'secrets of the honours system' five years ago. It had information in it. I also gave evidence at a Commons Select Committee in 2003. They [the police] just wanted copies of both."
Blogger Guido Fawkes, who mentioned the news on his website, also suggested that the police have questioned other journalists who have worked on the story.