Gardaí are investigating whether the motive for the murder of Kenneth O'Brien may have been of a personal nature.
The 33-year-old's dismembered body was found in a suitcase in the Grand Canal in Co Kildare at the weekend.
Phone records and CCTV footage are being examined for clues.
The murder inquiry team is also trying to find the location where Mr O'Brien was killed, and the rest of his remains.
They are also interviewing family and friends in a bid to uncover any issue of a personal nature that may have provided a motive for the murder.
Diesel fitter Kenneth, who had returned home from Australia in recent weeks, left his home in Clondalkin, west Dublin, last Friday and was never seen again.