Criminals are now deploying surveillance technology that was originally developed for use by police and military forces.
Gangland thugs are purchasing tracker devices, manufactured in eastern Europe, to target potential victims or keep tabs on suspect associates.
Although this is not widespread, at least two devices have been recovered by gardai investigating serious crime.
The latest tracker was discovered by garda technical experts as they examined a Toyota Avensis car after its occupants had been shot dead on the forecourt of a petrol station in west Dublin in November.
They found the device concealed in the rear of the Avensis and believe it had been planted there on behalf of the major Dublin criminal who had ordered a hit.
The device was then used by three hired killers to track down the car and kill the occupants.
However, gardai are examining the possibility that the wrong car was selected for the trace and that cousins, Glen Murphy (19) and Mark Noonan (23) were innocent victims.
They died in a hail of bullets after stopping the Avensis at a petrol station beside a Tesco supermarket at the Clearwater shopping centre in Finglas, shortly before midnight on November 23.
Neither of the victims was known to gardai as a gangland figure and officers say they could have been singled out in error.
But investigators stressed last night that they were keeping all options open and were still investigating the two men's backgrounds to establish if they had fallen foul of a gangland boss.
One of two automatic pistols used in the double murder had also been fired in two non-fatal shootings on the northside of Dublin, ballistic tests showed.
The two gunmen and their accomplice, who was driving their black BMW getaway car, had been seen in the forecourt about five minutes before the victims arrived in Mr Noonan's grey Avensis.
Gardai believe that a criminal gang with links to the northside was behind the murders although the BMW was thought to have been driven across the Border into the North after the incident.
Gardai have mixed views on whether the murders were a result of mistaken identity.
The clinical nature of the shootings indicated that it was a very well organised hit. But detectives have not yet found any clues as to why the cousins might be targeted although they are still pursuing a number of lines of inquiry.
Gardai have appealed to anybody with information to contact them at the incident room at Finglas station, 01 666 7532 or on the confidential line, 1800 666111.