If anyone wonders why Gerry Adams consistently denies IRA membership, the reason is now plain to see. There are reports that the file being prepared by the PSNI for the Public Prosecution Service recommends his prosecution for IRA membership.
So, Mr Adams, who was never convicted, is trapped in denial, unless he wants to face the courts and a possible jail sentence.
That would be limited to two years under legislation that followed the Good Friday Agreement. In fact, it would be highly unlikely that Mr Adams would be prosecuted, and if he were, that a judge would impose a custodial sentence.
It is not that anybody doubts that Mr Adams was in the IRA in 1972. It is even noted in official papers.
One secret document released in 2003 records a meeting on June 20, 1972 between Philip (later Sir Philip) Woodfield, who was an NIO official, Frank Steele, an MI6 agent, and the IRA.
"The IRA representatives were Mr David O'Connell and Mr Gerard Adams," Mr Woodfield wrote in his minute of the meeting.
PJ McGrory, the father of the present Director of Public Prosecutions, was brought along by the republicans as "a solicitor and wholly independent person".
He withdrew after verifying the authenticity of a letter from William Whitelaw, the Secretary of State, authorising Mr Woodfield to negotiate for him.
Adams had been released from internment two days earlier to take part in the negotiations. That is why he was free at the time of Jean McConville's abduction in December 1972.
The IRA had three conditions for an indefinite ceasefire – political status for IRA prisoners, a cessation of "harassment" of the IRA, and agreement to hold further meetings once the ceasefire was shown to be effective. The British refused political status, but got a 10-day ceasefire anyway.
There was another meeting in which Adams and other members of the IRA delegation, including Martin McGuinness, were flown to London onboard an RAF helicopter.
So, he acted like an IRA member, though if he denied it, proof that he was one may be difficult to pin down. Adams is now the only survivor of the June 1972 meeting.
Prosecuting would create a precedent, put stress on the peace process and open a Pandora's box.
Very few people were ever convicted of membership of proscribed organisations like the IRA or UVF, yet thousands served time for offences admitted by these organisations, or who are known to have been members.
The courts would never be finished if prosecutions were mounted against them all and cherry-picking would be unfair.
In the case of the IRA, we are talking about a group that has renounced violence, decommissioned its weapons and been inactive since the 1990s.
The police believe it poses no current threat and its structures are largely gone, so what can be gained?
There is also the fact that the maximum, two-year custodial sentence would be the same as the maximum allowable for the murder of Jean McConville, or any other Troubles-related crime.
There would then be little point in prosecuting murders or bombings with the softer option of membership available, and sentences would be concurrent anyway. That would seem demeaning to victims.
The PSNI won't complete its file for several weeks. It is still gathering evidence, with a further arrest yesterday.
It would be wise not to go down the route of IRA membership with any of the suspects if there isn't the evidence of more serious charges.
It is hard to believe that a judge would not offer Adams a discharge in return for a guilty plea.