A surveillance operation on a leading loyalist and suspect in the murder of GAA official Sean Brown that was lifted the night before he was shot dead is believed to have been carried out by the RUC.
Detail of the operation emerged as coroner Patrick Kinney abandoned the troubled inquest and confirmed he intends to write to secretary of state Chris Heaton-Harris to ask for public inquiry.
The development came after state agencies, including the PSNI and MI5, made applications for multiple redactions to sensitive documents connected to the murder under Public Interest Immunity (PII).
PII certificates are used by state agencies to withhold information they want to remain hidden from public view.
Mr Brown (61) was attacked, beaten and abducted by an LVF gang as he locked the gates at Bellaghy Wolfe Tones GAC, Co Derry, in May 1997.
After being placed in the boot of his own car, he was taken to a country lane outside Randalstown, Co Antrim, where he was shot six times.
Collusion has always been suspected.
During Monday’s inquest hearing it emerged that a surveillance operation on Mark ‘Swinger’ Fulton, a notorious member of the LVF in Mid Ulster, was stopped the night before the murder and picked up again the following morning.
It is now understood that operation was carried out by the RUC.
An inquest hearing last week heard that MI5 has claimed it has “no record of any intelligence” relating to the murder despite launching a spy operation against senior loyalists in Mid Ulster more than a year before Mr Brown was killed.
It is not known if the MI5 intelligence operation was linked to the surveillance of Fulton, who was a close ally of LVF founder Billy Wright, a notorious sectarian killer and suspected state agent.
In March 1997 Wright was sentenced to eight years after being tried for intent to pervert the course of justice and making a threat to kill.
According to the Billy Wright Inquiry report Fulton “assumed nominal leadership of the LVF”, however, Wright “continued to be in practice the acknowledged and undisputed leader even when in prison, and he continued to direct operations from his prison cell”.
Fulton has been named in court papers as a suspect in the murder of Mr Brown.
He is thought to have taken his own life Maghaberry Prison in 2002.
Last week the coroner heard that more than 25 people had been linked by intelligence to the murder, including several state agents.
At earlier hearings it emerged that a suspect in the murder was believed to be a serving member of the Royal Irish Regiment while another suspect held a personal protection weapon and was regularly visited by a police officer at his home.
A PSNI spokesman did not respond directly when asked to confirm if the surveillance on Fulton was carried out by police, adding that they “have nothing further to add in relation to this other than the statement that has been issued”.
In a statement on Monday, Chief Constable Jon Boutcher said the PSNI acknowledged the comments of the coroner and that he was determined to work with families impacted by the disclosure limitations of the coronial process.
“The Brown family, and indeed others, have been let down by the lack of a suitable mechanism to address sensitive information at inquests,” he said.
Solicitor Niall Murphy said the Brown family ask “why has MI5 sought three (PII) certificates on the grounds of national security, from a total of five PII applications, signed by the Secretary of State.
“What is it that MI5 have to hide from the family and indeed wider society?
“Who was it that decided that the surveillance on Mark Fulton be lifted the day before Sean’s murder?
“How many of the 25 suspects who were state agents at the time of the murder were serving RUC or RIR members?”
When previously asked, both the PSNI and Ministry of Defence failed to answer the question directly.
