Sources have revealed that officers have now spoken to virtually all of Kerins' associates, including the Traveller dealer who lives near where the murder happened.
The strongest line of inquiry still remains that Kerins was shot dead by a Traveller mob he previously associated with because they feared he would talk to gardai about their drugs operation.
The gang was also nervous that details would be provided by Kerins about the outfits involvement in the suspected murder of Tallaght man Gerard Daly, who vanished in June last year.
A senior source explained: "There have been no arrests yet, and gardai also have not recovered the shotgun that was used in this murder, but a number of individuals have been spoken to at length.
"These include criminals based in the Cavan area that Mr Kerins associated with in the months and years before his murder."
Gardai have also spoken to Kerins' pal, Anthony 'Fanta' Gorman -- the suspected INLA figure who now lives in the Baileborough area of Co Cavan and who was very friendly with the murder victim. 'Fanta' Gorman (42) -- who is not a suspect in the case, and who now works as an artist, is accused by the British authorities of being involved in the murder of a British soldier 20 years ago with notorious INLA figure Declan 'Whacker' Duffy, who was convicted of the offence in 2010.
Sergeant Michael Newman (34) was gunned down by the INLA outside an army recruitment office in Derby city centre on April 13, 1992.
The terror group, which announced it was disbanding in 2009, admitted responsibility for Sgt Newman's killing at the time. Fellow INLA member Joseph Magee was jailed in 2004 after pleading guilty to the murder.
John Kerins was blasted at close range by a shotgun as he sat in his home at Cornaveagh, Baileborough, Co Cavan.
Kerins was facing a Circuit Court trial and a possible jail sentence if convicted of the Co two Cork charges, which were investigated by officers from Togher Garda Station.
The stolen property was worth over €20,000 and the former detective was charged with stealing it in April of this year. It has also emerged that Kerins' estranged family have fled their home after last week's murder.
His wife Shirley Quinn and three children have now moved to a new location after the gun murder.
Kerins served 25 years as a garda after his graduation in 1983.
He had been based in many stations across the country and worked in the Garda Bureau of Fraud Investigation.
When working in the fraud squad Kerins was a suspect when a large sum of Swiss francs disappeared, but was never charged. He also escaped criminal sanction after he threw a torch at a youth travelling in a stolen car in 2002.
David Herbert (18) from Navan, Co Meath, later died in hospital from a fractured skull.