Wayne Bennett says Newcastle are clueless as to what they are being probed over by the Australian Crime Commission, but revealed investigators are looking at the NRL club's records as far back as 2005.
It's the first indication that investigations stemming from the ACC report into performance-enhancing drugs and organised crime in sport could go back over so many seasons.
Investigators from auditors Deloitte visited the Knights last week, and seven-times premiership coach Bennett said at a media conference yesterday that they checked on records as far back as seven years ago.
Bennett, who only took over as Knights coach for the 2012 season, said he had quizzed all staff and players and was confident the current Newcastle set-up had nothing to worry about.
"They want us to confess to something. I'm racking my head what we've got to confess to," said Bennett.
"I've been through the staff, I've checked with all the players.
"Whatever they're looking for, it hasn't happened in the past 18 months. So after that I've got no idea.
"We've just got no idea. We've complied with everything they've asked for and we'll continue to do that."