The Victorian Office of Police Integrity has accused The Australian newspaper of running a campaign against it as a strategic move in the run-up to tomorrow’s Federal Court hearing in the so-called Oz Leaks case.

Tomorrow The Australian and the OPI are before the Federal Court for a hearing in the ongoing attempt by the newspaper to suppress the OPI investigation of reporter Cameron Stewart’s terrorism scoop in August last year.

This morning The Australian ran the latest in a series of front page stories attacking the OPI. It rests heavily on a legal opinion by Phil Priest QC, who is also the lawyer working for the Police Association and former Assistant Commissioner Noel Ashby.

Priest accused the OPI of gross misconduct for inconsistent treatment of Ashby, who was charged with perjury after an OPI investigation, before the case collapsed because of a technical stuff up. But what The Australian did not reveal in today’s story — or in its many critical stories about the OPI in recent weeks — is that the paper is suing the OPI in an attempt to have its  investigation into Stewart’s leak declared invalid and its report, which is highly critical of the newspaper, permanently suppressed.

As previously reported in Crikey, this case is part of a murky series of dealings in which the reputations of Stewart, The Australian, the OPI and its federal counterpart, the Australian Commission for Law Enforcement Integrity (ACLEI), are all at stake.

This morning on the Jon Faine program on 774 ABC Radio, OPI Director Michael Strong vigorously denied allegations of misconduct in the Ashby affair, saying there was no inconsistency in making judgements by which some people were treated as reliable witnesses, and others as suspects.

He also said the OPI had a “dossier” of articles from The Australian, and expected more tomorrow and on Saturday, in which the newspaper had sought to discredit it. Strong declared himself “deeply suspicious” of the newspaper’s motives, saying the run of attacks was “too much of a coincidence”.

Tomorrow’s Federal Court hearing relates to an OPI investigation into the source for Cameron Stewart’s scoop of August last year, in which he broke the news of a joint federal and state police anti-terrorism operation on the very morning on which raids were carried out and suspects arrested. A Victorian police officer has been stood down, suspected of being his source.

The Australian has succeeded in obtaining Federal Court orders that prevent the OPI from releasing a report into its investigation into the affair, and from briefing state and Commonwealth prosecutors about what are said to be “serious criminal offences” committed during Stewart’s research.

The OPI has said in previous court hearings the key piece of evidence with which it wants to brief prosecutors is a transcript of an interview with Stewart, in which he gave evidence voluntarily. It’s understood Stewart disputes the interview was in any real sense voluntary — The Australian wants the investigation declared invalid and all the evidence gathered permanently suppressed.

Meanwhile the ACLEI, which was originally part of the court case, cut a deal with The Australian in March which released the paper from the legal action in return for promising not to publish any of the evidence gathered. The ACLEI has said it will write its own fresh report on the investigation, but has given no time line on when this might be done.

Today’s article, and Strong’s response, make tomorrow’s hearing a high stakes game indeed. And who can doubt that for decades to come, it will be a case study on the relationship between journalists and their sources.