NUJ Irish Secretary Seamus Dooley made the call after Detective Chief Inspector Charles Patterson told an inquest into the Sunday World investigative reporter's death that he believed eight men questioned about the killing were behind it.

Mr Dooley said this "represented an admission of failure to deal with one of the most significant unsolved murders in Northern Ireland".

"We find the approach of the PSNI unacceptable and at this stage the only solution is the involvement of an outside police force," he said.

An inquest into the father-of-four's death was held at Armagh Courthouse yesterday. Coroner John Leckey concluded that Mr O'Hagan was gunned down close to his Lurgan home for exposing the drug dealing activities of loyalist paramilitaries in the Mid Ulster area.

The 51-year-old and his wife Marie were walking home from a night out in a pub on September 28, 2001, when a car pulled up alongside them and a passenger shot him three times.

The LVF later claimed responsibility for the killing although no-one has ever been brought to justice for it. Mr Patterson told the hearing that eight men had been arrested and questioned in the weeks after the murder.

"I'm quite happy that the people arrested at that time were the people responsible for this murder. I don't have the evidence to proceed against them," he said.

Mr Leckey said the bravery of journalists seeking to expose criminals must be recognised. He said he believed Mr O'Hagan was the only journalist to be murdered in Troubles-related circumstances in Northern Ireland.

Mr O'Hagan's wife Marie was the first witness to give evidence at yesterday's hearing.

She recalled her horrific memories of Mr O'Hagan being shot as they approached their home hand-in-hand.

"I became aware of a car slowing down. I saw a gun in one of the windows.

"Martin became aware of the car and pushed me towards the hedge. I fell into the hedge and heard a number of shots. Martin shouted 'Marie, get an ambulance'," she said.

The widow then ran to their nearby family home and raised the alarm. When she returned, Martin seemed unconscious. He was declared dead by an ambulance crew which quickly arrived at the scene.

Mr Patterson said the murder inquiry remained alive but admitted it was not actively being worked on.

However he said the case would be internally reviewed by the PSNI in the New Year.

Jim McDowell, northern editor of the Sunday World, called for the review of the case to be held urgently.

"If the case has hit a brick wall bring in fresh faces, open a fresh file and let's get Martin O'Hagan's killers where they belong - behind bars," he said.

Speaking before opening the inquest, Mr Leckey addressed a number of criticisms made by Mr McDowell in a interview on Radio Ulster yesterday morning, including one that the inquest was being held so close to Christmas.

The coroner stressed that Mrs O'Hagan had been consulted on the date of the hearing and had been offered a date for the New Year, possibly in February.

"I can state that this inquest would have been adjourned if Mrs O'Hagan had not been happy," he said.