A number of possible motives have emerged, with sources saying there is intelligence to suggest he was linked with a number of forms of criminality, including drug dealing.
Gardaí also believe a criminal known to Kerins feared he was on the brink of a mental breakdown and was about to implicate him in the case of Gerard Daly (44), originally from Tallaght, Dublin, who disappeared almost 18 months ago and is now feared murdered.
“There is a lot in the background here and a lot of work to be done before you could be clear he was killed for one reason rather than other possible motives,” said one source.
Other sources said since leaving the Garda, Kerins appears to have developed into a “wheeler dealer criminal”, with various contacts with drug dealing, robbery and Traveller-based gangs in a number of counties.
Gardaí have begun to build a complex road map of the last months of the murdered former detective John Kerins in a bid to establish a motive for his shooting dead at his home late last week.
