After Barry McCaffrey was arrested on August 31st, he was escorted from his house on a quiet Belfast street by armed police in boiler suits. “The whole street was swarming with police,” says McCaffrey. “Some of them had taken up position among the trees across the road.

“As I was being driven away I saw one of my neighbours, an older lady, out walking her dog. Our eyes met and I could see a look of shock and horror on her face. She doesn’t know what I’ve done.

“Nor do the parents getting their kids ready for school. All they know is there are armed police all over the place and it is all down to me. It must have looked like I was a drug dealer or a mass murderer or something,” he says.

The police arrived at 7am. They produced a search warrant, and McCaffrey let them in. He washed and dressed under the eyes of an officer. Asked for computer and phone passwords, he supplied them. He even offered tea. “I’m a law-abiding citizen,” he said.

McCaffrey is an award-winning Belfast investigative journalist, the reporter behind Alex Gibney’s 2017 documentary about the 1994 Loughinisland pub massacre, No Stone Unturned.

The film makes use of, and shows what appears to be, a draft of a Police Ombudsman report from 2011. It was sent anonymously in the post to McCaffrey. As well as the ombudsman’s office, the PSNI would also have had access to this material.

That morning Trevor Birney, the producer of No Stone Unturned, was at home with his wife, Sheila, and their three daughters, along with relatives visiting from England. It was his eight-year-old daughter Freya’s first day back at school.

Knock on the door

When a knock came to the family’s door, Sheila looked out and saw what appeared to be about 30 armed police officers, uniformed and in plain clothes, alighting from vehicles. The house quickly filled up with police. His eight-year-old became frightened and began to sob. Birney, who had, like McCaffrey, to shower and dress in front of an officer, told his wife he was being arrested, and was taken away.

“For all the ugly aggression of the operation, the search itself was farcical,” says Sheila, who watched officers bag up items including a small, pink, broken mobile telephone.

Later, at the PSNI’s Serious Crimes Unit, the journalists were told that “on October 4th, 2017, the Police Ombudsman for Northern Ireland reported the theft of two ‘secret’ documents from their offices”.

The arrests, they were told, were in connection with suspicion of theft, the handling of stolen goods, the unlawful disclosure of information and the unlawful obtainment of personal data.

Although the investigation was led by Durham Constabulary, the officers involved in the searches were PSNI, who “threatened to break down” doors in offices shared by Birney’s company, Fine Point Films. “I said, ‘Why don’t you just ring the bell?’ ” Birney says now. Speaking to reporters after they were released, McCaffrey had said simply: “It’s us today, tomorrow it could be you.”

In a statement, Durham police, who had been asked to take charge by the PSNI, said “the investigation is solely into the alleged theft from the Police Ombudsman of Northern Ireland”.

“The theft of these documents potentially puts lives at risk and we will the follow the evidence wherever it leads us,” said the Durham statement, adding that the arrests were “significant” and that the papers were “sensitive”.

There is plenty that is strange about these events, and strangest of all is this: the Police Ombudsman of Northern Ireland, Dr Michael Maguire, had never reported the theft of documents from his office.

In a statement to The Irish Times, his office explicitly denied that he had done so. “We did not make a complaint of theft.” The ombudsman’s office said it understood the PSNI had commissioned Durham Police to investigate the means by which the film’s production team had secured access to the documents.

The ombudsman’s office had known in advance that the film would rely “very heavily” on the ombudsman’s 2016 published report: “Late in the day we were told that it would also use documentation which may or may not have come from the office.

“At no point were we made aware that this material may have been taken from the office,” it said. In reply to another question it emphasised that “the format of the document shown in the documentary is different to any similar document that we would have”.

Released without charge

The duo were released without charge on what is known in Northern Ireland as “pre-charge bail”. Under its terms, they must inform police three days ahead of travel outside the jurisdiction – including the Republic. They return for further questioning on November 30th.

No Stone Unturned takes its title from a promise made to Claire Rogan in June 1994, at the wake for her young husband, Adrian, who was murdered along with five other men at the Heights Bar in Loughinisland, Co Down.

There, an RUC officer assured her that they would “leave no stone unturned” in pursuit of the gunmen who burst into the remote pub, one of them shouting “Fenian bastards” before they shot the men in the back as they watched Ireland play Italy in the World Cup.

Interior of O’Toole’s bar in Loughinisland on the morning after the UVF shot dead six people there. File photograph: Pacemaker

Twenty-four years on, no one has been convicted for the slaughter, though compelling evidence was available from the start. In the film Rogan tells Gibney: “They didn’t lift a stone, let alone turn one.”

In June 2016 Maguire’s report on his review of the Loughinisland murder investigation found that there were “catastrophic failings” and that collusion between the RUC and the Ulster Volunteer Force had been a significant feature.

Special Branch officers had withheld intelligence from other branches of the RUC, enabling the gang to operate freely. The investigation, said Maguire, had been characterised by “incompetence, indifference and neglect”.

McCaffrey began investigating Loughinisland after he got his first job as a reporter with the Down Democrat in 1997. For years the families had waited for results from the police. In 2001 they complained to Dr Maguire’s predecessor as ombudsman, Al Hutchinson.

Four years later they voiced their anger to McCaffrey about how long Hutchinson was taking. When he did report, Hutchinson criticised the murder investigation, but found “insufficient evidence of collusion”. The families were bitterly disappointed.

In 2006 Rogan and her daughter Emma had spoken to McCaffrey about their suspicion that the police were protecting an informant. In time he discovered a litany of failings – not least the destruction of the getaway car.

In 2012 they asked McCaffrey and Birney if they would make a film to bring the Loughinisland story to the screen. When it came, No Stone Unturned produced headlines globally.

In one interview retired police officer James Binns told of how an interrogator had spent just 10 minutes out of a two-hour interview questioning a suspect. The rest of the time, he alleged, was spent urging the known UVF gunman to kill another Catholic.

The film-maker had multiple sources, many of them anonymous, but including ex-RUC officers. It drew on the documents posted to McCaffrey in 2011 as well as on the published June 2016 Ombudsman’s report.

Maguire, in his report, anonymised the three men in the UVF gang, which had been involved in other atrocities. The film named them. Today one of the gunmen still lives close to Loughinisland.

Birney and McCaffrey insist they and director Gibney behaved responsibly in deciding to name the murderers. “We discussed doing so with senior people at the ombudsman’s office in autumn 2016, knowing it was their responsibility to pass this on to the police,” said Birney.

“I met Assistant Chief Constable Stephen Martin in early 2017 and he told me [then] deputy chief constable Drew Harris had been briefed soon after the 2016 meeting,” he adds. (Harris is now the Garda Commissioner.) “We took comfort from that. As journalists we cannot assess risk – the only party that can do that is the PSNI. They could have warned the suspects and they could have injuncted us.”

Maguire strongly advised Gibney not to name a UVF informer. That advice was taken. Maguire saw the film before its release. The film-makers knew he would be obliged to inform the PSNI of its contents, and on October 4th last year, he did so.

In his statement to The Irish Times, Maguire explained: “We briefed PSNI that [the film] had identified a number of individuals, who may be now at risk, and that it had shown extracts from what appeared to be a Police Ombudsman document, albeit in a different format to our document.”

No injunction

The PSNI thus had time to seek an injunction blocking the film’s release. It did not. The film had its premiere three days later in London, before going on general release. A week later Maguire took part in a cordial discussion with Birney after a showing of the film in Belfast.

The arrests took place during a public consultation run by the Northern Ireland Office on proposals for dealing with the legacy issues left by the Troubles, including the nearly 1,200 unsolved murders.

PSNI Chief Constable George Hamilton accepted the conclusions of the highly critical second ombudsman’s report from Maguire, and welcomed the legacy proposals. But, he has frequently expressed frustration about the burden investigating the past places on his force.

Meanwhile he is under pressure from the Police Federation, which is highly critical of the ombudsman’s office and rejects the legacy proposals. Officers are angry, says its chairman Mark Lindsay, because they feel they are being subject to a “witch hunt” by a “morally wrong” system that now equates the actions of terrorists and police officers. The Association of Retired Police Officers is seeking to have the power to challenge ombudsman reports.

Defending the two journalists, Emma Rogan, Claire’s daughter, said the Loughinisland families believe that Birney and McCaffrey have acted throughout with “the utmost integrity”.

McCaffrey said police took away confidential documents not linked to Loughinisland: “I had to go and tell people who had trusted me with sensitive information. I felt ashamed. Why would anyone feel safe coming to me now?”

Just a fraction of the material seized from their homes and office had been linked to No Stone Unturned, said Birney: “We are just collateral damage in battles over the failure to deal with the past.”

The men’s solicitor, Niall Murphy of KRW Law in Belfast, said Durham Constabulary’s claim on the day of the arrests that the ombudsman’s office had “reported the theft to PSNI” must now “be compared to Dr Maguire’s confirmation that he has not made any such complaint”.

The fact that the complaint was never made “undermines the entire integrity of the decision” to arrest the journalists, said Murphy, who added that he will now seek to have the arrests declared illegal. Durham Constabulary and the PSNI, questioned by The Irish Times, both said that they could not comment “due to ongoing legal proceedings”.