The Regional Development Minister, a former IRA prisoner from south Armagh, ought to have a good idea. So too should Gerry Adams, who said he did not believe there was “any republican involvement in this murder”.

Jim McAllister offered up a different opinion, and he ought to know as well — a Sinn Fein councillor in south Armagh for years, he split with the party during one of the many twists in the peace process.

Speaking on behalf of the Quinn family, he said they believe IRA members were behind the brutal attack that left the 21- year-old dead on Saturday night.

Garda sources also indicated that the killers were IRA members, although they said the intention of the attack may not have been to kill.

Which leaves a conundrum that the DUP — warning of “serious repercussions” in the political process — will look to the Chief Constable and the Independent Monitoring Commission to resolve.

Officially the IRA has stood down its units, but the Provisionals' leadership still exists, at least in the form of the Army Council.

The IMC has said repeatedly that they have not been involved in any paramilitary activity, and IRA members have been ordered to refrain from “all activity”.

But south Armagh — touching on the area where Paul Quinn was killed — has been a difficult scene for reconciling developments in the peace process and the traditional activities of republicans.

Weeks after the IRA ceasefire was declared in 1994, members of the south Armagh unit killed postal worker Frank Kerr in Newry. The IRA said the killing had not been sanctioned by the leadership.

Thirteen years later, there is the possibility that Paul Quinn was killed the same way — a breakdown in the IRA's chain of command.

But there have also been important strides forward in terms of policing in the area. The idea that Northern Ireland's police would sit down at a public meeting in Crossmaglen was unthinkable at the time of Frank Kerr's murder.

But it has happened now.

Mr Adams' intervention yesterday was telling. In the morning, soon after the DUP laid out their concerns, he set out to put clear green water between Sinn Fein and the killers.

He condemned the killers as “criminals” and said people with information about the killing have “a duty” to pass it on to gardai and the PSNI.

This was the important matter as far as Taoiseach Bertie Ahern was concerned, underlining recent strides forward in policing in south Armagh.

Unionists are bound to be concerned that Mr Adams is saying what needs to be said to preserve the Stormont Executive. Their solace may be in the actual cooperation Gardai get.