Gardai have made "significant progress" in their hunt for the gang linked to the stolen car used in the murder of Detective Adrian Donohoe.
As the first anniversary of his death approaches, officers say they are as determined as ever to bring charges against those involved in his murder.
A huge crowd of gardai attended a Mass to remember the brave detective in Dundalk, Co Louth, on what would have been his 42nd birthday last Tuesday night.
Gda Donohoe was murdered during a botched robbery by a local gang at Lordship Credit Union on the night of Friday, January 25 last year.
There will also be an anniversary Mass in his honour later this month.
A source said: "Some people may be suggesting that this investigation is going nowhere but that is not the truth at all.
"Very good CCTV and mobile phone evidence has been gathered. One line of the investigation being vigorously pursued at the moment is the link between the murder gang and the stolen car."
The graphite blue Volkswagen Passat was stolen from Clogherhead, Co Louth, between 11.30pm on Tuesday, January 22 and 4.30pm on Wednesday, January 23, 2013.
The 08 D-registered automatic car was found burnt out at Cumsons Road, Newtownhamilton, Co Armagh, at around 10.30pm, about an hour after the murder.
Two men have already been questioned about stealing the Passat but no charges have been brought.
While they are actively working on the case, gardai believe that just one member of the gang involved in the attempted armed robbery is likely to face murder charges.