The PSNI's heavy-handed reaction to Sunday Tribune Northern Editor Suzanne Breen, over her interview with a Real IRA army council representative is an unnecessary, inconsistent and worrying infringement of press freedom.

To threaten her with sanctions under the Terrorism Act 2000 and to pursue a court order to seize notes, papers, photos, recordings, her computer and email and phone records, amounts to harassment of a journalist carrying out legitimate work within a democracy.

The publication of interviews with anonymous sources isn't something any newspaper takes lightly. On the record, accountable information is vastly preferable to anonymous interviews or behind-the-scenes briefings – whether by ruthless terrorists or government spin doctors.

But the fact is, information that is in the public interest isn't always easily come by. The fact is too, that the Real IRA does exist. The ferocity of their hatred had just been felt by two young soldiers preparing to leave the North for a tour of duty in Afghanistan. Sappers Patrick Azimkar and Mark Quinsey lost their lives at the hands of the Real IRA. Two pizza delivery men – one Polish – were also badly injured.

This was a major national and international news story. The need to get the full story behind the ferocity of their deeds is a legitimate journalistic pursuit. Not just that, it is incumbent on the professional reporter, as part of his or her duty, to find out about the people behind these acts of violence, to try to contextualise their destabilising presence.

Unfortunately, their ability to enlist disconnected and disgruntled young men from the North's least advantaged enclaves into their warped ideology is an unpalatable reality.

That isn't to say that the views of the men of violence who live outside the acceptable norms of society, who break laws in the most repulsive fashion, should be given a blank sheet to air their grotesquely distorted and undemocratic opinions.

But Suzanne Breen, this newspaper's Northern Editor, is an experienced professional with many years of covering the North from its darkest days of violence, to the emerging peace process and today's more stable times. Her stories have always been accurate, and her analysis astute and widely respected by all sides in the North and South.

She has taken terrorist claims of responsibility many times and interviewed numerous paramilitary groups for stories in the past, yet this is the first time the police have intervened with threats of court orders to search her home and property.

All the information with which she was provided – anonymously – by the Real IRA member she interviewed, was published in the Sunday Tribune. Nothing has been hidden, nor has any agenda been pursued. The Real IRA interview was a basic job of journalism and one Suzanne achieved, in the public interest, because her independence and ethics are unquestioned.

It is a cornerstone of journalism that sources be protected. The Sunday Tribune fully supports the investigation into the murders at Massereene barracks and that of Denis Donaldson, but we will rigorously defend to the highest level Suzanne Breen's right to maintain the confidentiality of her sources.

The reporter isn't a detective, nor is he or she a witness or 'informer'. If the role of messenger is interfered with so that the journalist becomes a state witness, then his or her credibility is destroyed. There is also the sinister reality that if Suzanne Breen cooperates with the police, her life would be endangered.

Ten years ago, when former Northern Editor Ed Moloney was threatened with similar legal sanctions after interviewing William Stobie, the man charged with murdering solicitor Pat Finucane, this newspaper began a long legal battle to prevent him from having to hand over his notes – and won.

We intend to be just as vigorous in our defence of Suzanne Breen's right to keep her sources confidential - and once again, we will do so to the very highest level.