The officer who will head the 'Stakeknife' probe has briefed UK police chiefs on the investigation as he assembles his team.
UTV understands that already there has been "a high level of interest" from officers wanting to join the investigation, and some detectives have already been released by their forces to begin work.
Bedfordshire Chief Constable Jon Boutcher - who will lead Operation Kenova - is also close to appointing an oversight team that will offer support and advice as the investigation develops.
It is thought it will include senior international police figures.
Their names and a terms of reference will be published on the Operation Kenova website when details are finalised.
Boutcher has briefed the National Police Chiefs' Council and has also written to chief constables across the UK.
Places on the investigation team have been advertised - with that ad due to be extended beyond this Sunday.
It is understood that Boutcher has now also identified the London building that is his "preferred option" as the headquarters for the investigation.
He does not intend to reveal the precise location.
By the end of September, he hopes to have a team in place to begin the first phase of the investigation. This will involve gathering and assessing information held by a number of agencies.
Operation Kenova will examine the alleged activities of an Army Agent operating inside IRA 'internal security'. Freddie Scappaticci - a Belfast republican interned in the 1970s - has denied he was Stakeknife.
Boutcher will not say when he intends to first interview the agent.
His investigation will also examine what information was available to the various intelligence agencies - military, MI5 and RUC Special Branch - and when that information was available.
The IRA will also be put under an investigative spotlight as the detective team examines dozens of murders - what the IRA would have termed the "executions" of suspected informers/agents.
In May, UTV revealed that Jon Boutcher had been approached to lead the investigation - his role confirmed several weeks later.
Speaking at a news conference in Belfast in June, Boutcher said "the truth will be a difficult and elusive prey", but he said he was committed to finding it.