By Mark Simpson
BBC Ireland correspondent
As reporters gathered outside police headquarters in Belfast for a news conference with the chief constable, there was a grim sense of deja vu.
Chief Constable Sir Hugh Orde acknowledges the threat level is high
During the Troubles, late night statements from police chiefs about the latest murder in Northern Ireland were part of the daily routine.
In those days, there was an ugly cycle which journalists used to follow - death, reaction, funeral; death, reaction, funeral.
Following the killing of two soldiers in Antrim, the murder of a police officer in Craigavon two days later feels like the start of a new cycle.
But, at this stage, it is only a feeling.
Two attacks in three days shows a determination to keep killing but, at present, there is no evidence that dissident republicans have the ability to sustain the same intensity of violence perpetrated by the Provisional IRA for three decades.
That was certainly the view of Chief Constable Sir Hugh Orde when he spoke to the media at 0120. He called the dissidents a small group of "criminal psychopaths", and warned against giving them more credibility than they deserved.
Nonetheless, he acknowledged that the threat level is high and these are dangerous times.
Sir Hugh, who used to work for the Metropolitan Police in London, now faces the most difficult challenge of his career in Belfast.
He is known as a tough cop, but at one stage during the news conference, his voice seemed to flicker with emotion. Clearly, the death of one of his colleagues had affected him.
Constable Stephen Paul Carroll is the first officer to be killed by paramilitaries during Sir Hugh's seven years as chief constable.
For his predecessors, it was an all too common occurrence. Between 1969 and 1998, a total of 302 officers were murdered.
The security services are working hard to make sure Constable Carroll is the last to die.
But what can they do now that they have not done already? Bring troops back onto the streets of Northern Ireland?
That does not seem likely. Even in the wake of the Antrim Army base attack, Sir Hugh said "categorically" that he had "no intention of bringing the military back into the routine of policing".
So what about a police round-up of suspected dissidents in Craigavon and elsewhere?
Again, that does not seem likely. Unless the police have hard evidence against individuals, a series of swoops would have the potential to inflame opinion in working-class, republican areas. It could actually help the dissidents gain support.
The biggest weakness of groups like the Real IRA and Continuity IRA at the moment is their lack of significant public support. They know this themselves. That is why they do not have a political wing which contests elections.
During the 30 years of the Troubles, the Provisional IRA had Sinn Fein; the dissidents have no electoral machine. What they do have is weapons and explosives. Perhaps, only a small amount, but they have shown in recent days they have people who are prepared to use them.
There is speculation that they may have suddenly increased their supplies in recent months and that is why the authorities raised the level of threat from substantial to severe. Clearly, something dictated that sudden change, but no-one on the security side is prepared to say exactly what it was.
Sir Hugh Orde will know, but for operational reasons, he will not say.
He is the man with arguably the toughest job in Northern Ireland at the minute, and he is not getting much sleep.
Like everyone else, he will be desperately hoping he will not have to attend any more late-night news conferences.