Donegal coroner Dr Denis McCauley has asked for a report on the garda investigation into the murder of 24-year-old Andrew Allen, who was shot dead in a house in Buncrana in February 2012.
Mr Allen, who was from the Waterside area of Derry, had been living at the house at Links View Park. A group calling itself Republican Action Against Drugs claimed responsibility for the killing.
Inspector David Murphy asked today at Buncrana courthouse for a further adjournment of the inquest into Mr Allen's death.
He said that a number of strands in the inquiry are still open and being assessed by the investigating team.
Inspector Murphy said he was conscious that the sixth anniversary of Mr Allen's death had passed but there are very extensive inquiries still being pursed in this matter.
Agreeing to an adjournment to September, Dr McCauley asked that the gardaí make a reasoned argument to him then as to why he should not set a date for an inquest after six years.
Without interfering with the investigation, he said, he would like an assessment as to the likelihood of this case being successful.
Gardaí issued a renewed appeal for information in the case on the sixth anniversary of Mr Allen's death on 9 February last.
Speaking then, Det Insp Pat O'Donnell said: "We are following several lines of enquiry and are very confident we will succeed in bringing the person or persons who committed this crime to justice."
There have been five arrests in the course of the investigation but no one has been charged in connection with his death.