Gardai are keeping an open mind on who carried out the murder 39-year-old haulier Mr Ciaran Smyth. Mr Smyth, originally from Mullaghbawn in south Armagh but living in Ravensdale, Dundalk, was shot in the back and side of the head with a shotgun.
His body was found in a cattle pen near Curraha, Co Meath, on Friday afternoon, four days after he had last been in contact with a family member.
Gardai are investigating the possibility that the murder could be related to allegations that Mr Smyth was engaged in money-laundering and cigarette-smuggling.
Mr Smyth, who had no convictions, was a close associate of a leading member of the "Real IRA" and is believed to have laundered money for the organisation.
Detectives are looking at the possibility he may have been murdered as a result of money going missing but were quick to discount reports that republican paramilitaries were prime suspects.
"We don't know who murdered him and are keeping an open mind," a Garda spokesman said.
The post-mortem by the Assistant State Pathologist suggests that Mr Smyth was probably killed on Thursday night/Friday morning. Yesterday, Chief Supt Michael Finnegan, of the Louth-Meath division, who is heading the inquiry, appealed to the public for help.
"We are asking anyone who saw anything suspicious in the Kilbrew Lane/Curraha area anytime on Thursday night or Friday morning to contact us at Ashbourne Garda station on 018351515," he said.
Members of the Garda Technical Bureau examined Mr Smyth's detached house yesterday afternoon. No spent cartridges were found at the site.
It was not unusual for him to be away from the house for days at a time, but when his family failed to reach him on his mobile telephone they reported him missing to gardai in Dromad at lunchtime on Friday. Shortly afterwards a motorist came upon his body in a field off Kilbrew Lane.
It is believed he was shot in the field. He was dressed in a tracksuit, which he was not wearing when last seen on Monday night, and there were injuries to the body, suggesting he had been beaten.
Garda sources confirmed they had identified the body by fingerprints, which were taken during his time in Garda custody as part of the investigation into the murder in Dundalk in 1999 of a Newry businessman, Mr Richard McFerran.
It is alleged that Mr Smyth and Mr McFerran made vast amounts of money from cigarette-smuggling. Members of the Garda Fraud Bureau and the Criminal Assets Bureau also arrested Mr Smyth in relation to alleged money-laundering at a bureau de change in Dromad.
That arrest was part of the ongoing Garda investigation into an alleged multi-million-pound cross-Border money-laundering operation. Only one man has been charged with related offences.
Gardai have denied suggestions that Mr Smyth was involved in drug-smuggling or that he was connected to a murdered drug-dealer, Paddy Farrell. A team of detectives is working on the murder investigation and an incident room has been set up at Ashbourne Garda station.