When will Sinn Fein condemn atrocity?

It is 40 years since a young Gerry Adams and Martin McGuinness walked out of the old official IRA.

Better than anyone, they know how a small splinter group can grow in power and status if it is ruthless enough and goes unchallenged by the old guard.

After all, their own splinter, the Provos, became the most efficient terrorist organisation in the world.

Today the pair have a lot of explaining to do about the resurgence of cold-blooded murder as a Republican political tool.

At the start of the peace process they gave commitments that the men and guns of the armed Republican movement would abide by the Good Friday agreement.

There was talk of the infamous "discipline" of the Provisional IRA being brought to bear on dissidents and hotheads who disagreed with the line.

After a decade of solid progress the province has been transformed. House prices have soared, businesses are prospering, migrants are pouring in not out, the Army is off the streets and a civilian police force is finding its feet.

And there is the astonishing prospect this month of Mr McGuinness being feted by Barack Obama at the White House alongside First Minister Peter Robinson, a veteran unionist.

But while Adams and McGuinness have moved away from their terrorist past, the Real IRA and its rival splinter the Continuity IRA have been growing in activity in the background.

Over the past year the Real IRA has gone to strenuous efforts to kill a police officer, without success, even pumping bullets into the chest of an off-duty father waiting to collect his children from primary school.

They also prepared a 300lb home-made bomb, which would probably have been used to attack an army barracks.

There have been dozens of incidents that did not blip on the Westminster radar but showed the new hardliners preparing to announce themselves with a major atrocity.

In the 14 hours before Mr Adams reacted to Saturday's attack, the Sinn Fein president would have consulted Provisional IRA godfathers on what he should say to the media.

But even in a BBC interview today he still refused to condemn the killings as murders or express sorrow for the families.

Similarly, Mr McGuinness criticised the killings, not because they were wrong, but because they were bad strategy.

The Sinn Fein pair know the Real IRA leadership well.

The question is when Adams and McGuinness will challenge the hardliners properly, beginning with a full-hearted condemnation of the Massereene killings.