The death of a second officer in the Garda District of Dundalk is being seen as further evidence of what police have been quietly describing as a 'disastrous' reduction in gardai and PSNI numbers along the border.
There is now what one senior figure described as a 'corridor of lawlessness' along the border which once had 38 operational stations along its hundred-mile length. This has been reduced to a handful of 'full-time' stations between Londonderry, Enniskillen, Monaghan and Dundalk.
The area has seen a boom in all sorts of crime since the end of the Troubles as former terrorist groups - both loyalist and republican - embarked on building crime empires. Small time gangs of robbers and extortionists also sprang up as police were withdrawn in large numbers from both sides of the border.
On the northern side, policing has been reduced to what one PSNI source described as 'skeleton' levels due to cuts in resources in recent years.
This was seen at the time of the Det Garda Adrian Donohoe murder when the culprits were able to drive unheeded into south Armagh, burn their car and escape into the countryside where they were protected by local families, including one with links to the local IRA leadership.
Almost 20 gardai have been murdered in the course of their duties in the past half century, most of them by the IRA or its off-shoots.
Yesterday evening's scene, however, was not believed to be linked to any terrorist or organised criminal but seemed more likely to be linked to a domestic siege or 'barrier-type' incident, as it is known to police.
The murder of Mr Donohoe in Dundalk, a few miles from the scene of last night's murder, was preceded by a small number of incidents in which gardai have been murdered on duty.
In July 1999, Sergeant John Callanan died after he was doused with petrol and set on fire by a deranged man in the foyer of Tallaght Garda Station. Another Garda Sergeant, John Joe O'Connor, was shot and killed while protecting his son from another deranged man in Tralee, Co Kerry.
Det Sergeant John Eiffe (40) died when he was hit by the ricochet of a bullet during an armed bank robbery in Abbeyleix, Co Laois in December 2001.
Twelve gardai were murdered by the IRA and another five killed by off-shoot republican terror groups during the Troubles. The last officer murdered by the IRA was Det Garda Jerry McCabe, shot dead as he carried out a routine protection patrol for a cash-in-transit van in Adare, Co Limerick in June 1996.
Along the border, and in south Armagh, the open and massive local fuel smuggling business has gone virtually unhindered since the so-called IRA ceasefires and the 2006 'order to dump arms'.
This was followed by the IRA's October 2008 murder of innocent local man Paul Quinn (21) by an IRA squad - a murder that has gone unsolved due, gardai say, to a 'wall of silence' erected by republicans in south Armagh.
In the aftermath of the Donohoe murder, gardai increased patrolling for several months but no significant extra resources were allocated to border stations where crime has been rising steadily in the past two decades.
The failure to arrest and charge Donohoe's killers has been described by one senior source as 'the greatest disaster' in the recent history of the force in that, in his view, it sent out a message that gardai can be killed with little prospect of arrest or charge.