Gardai are investigating whether a phone used by Mr Justice Michael Moriarty was tapped in the lead-up to his damning report.
Mystery surrounds the circumstances which led the judge to believe that his private office and home phones may have been compromised.
So far special detectives have no devices or evidence that phone lines were tampered with but intense inquiries are continuing.
Technical officers are now understood to be looking at whether the exchange through which the calls were routed could have been tapped.
In a bizarre twist, they are also set to carry out tests on the underground cabling leading into the office system.
A source said: "There appears to have been some sort of incident a week before the report was published that sparked serious concerns that a third party was gaining information.
"It's a really unusual situation and the exact nature of what was going on has not yet emerged."
There has been a suggestion that the phone was being monitored by an unauthorised third party and conversations recorded.
As part of their investigation, officers from the Garda Crime and Security Unit also checked computer equipment and carried out a sweep of the tribunal's offices in Dublin Castle.
Such sweeps are very rare and are usually reserved for events where high-profile individuals such as the President are attending.
The Moriarty Report, which runs to more than 2,000 pages, has caused massive controversy in political and business circles as it suggests TD Michael Lowry supplied substantive information to Denis O'Brien during the licensing competition in 1995.
The fallout from the publication continued over the weekend as it emerged that a personal adviser to Taoiseach Enda Kenny worked for Deputy Lowry when he was minister for communications. Mark Kennelly is not actually mentioned in the report.
Persona -- which was runner-up to Mr O'Brien's consortium -- also called for the State to refund the expenses of all the unsuccessful licence bidders.
The group is already suing the State over the debacle and has now claimed that the report heightens its case.
Tony Boyle, of Persona, has called on the Government to concede that the process was flawed.
"We have no desire to add further to the economic woes of the State.
"We do believe that all money that all people spent, for all bidders, should be returned," he said.
"Thereafter, if there is any place for damages it must be directed to the parties who acted incorrectly."