Three members of a family were still being held today in connection with the death of Kenneth Fetherston, whose remains were found in a remote mountain area three weeks ago.
Two brothers, aged 23 and 29 and their mother, were still in custody today while the father was released last night.
The brothers, who were arrested yesterday, were being questioned about the murder at Tallaght and Rathfarnham Garda stations.
The mother was detained on Wednesday in Gorey on suspicion of withholding information about the crime and taken to Tallaght. The brothers' father was arrested in Rathfarnham also on Wednesday and held overnight in Tallaght.
He was released without charge yesterday afternoon and a file will now be prepared for the Director of Public Prosecutions to determine if criminal charges should be brought.
It is believed Kenneth Fetherston (26), the father of a three- year-old girl, was killed because he asked for the repayment of money he had lent to someone.
The size of the debt has not been established but his father Brian is satisfied that it was over €10,000. The money was part of an accident compensation claim paid to Mr Fetherston.
Originally from Aylesbury in Tallaght, he left his apartment at the Tallaght Cross Hotel before 9am last September 22. He was seen at his car repair business at Landy's Industrial Estate on the Knocklyon Road in Dublin before 10am.
His red Honda Civic was found four days later in a lay-by on the N11 near Gorey, Co Wexford. There were traces of blood in the boot and on the bumper.
Three weeks ago Mr Fetherston's skeletal remains and his clothes were discovered in a boggy ditch off Military Road in Rathfarnham by two people out walking. Dental records and DNA tests confirmed his identity.
Kenneth's three-year-old daughter Nicole has been told that her "daddy has got a new job as an angel with Holy God".