While Christine Nixon, the Victorian Police Commissioner, appeals for calm in the wake of the arrest of a man last Friday for alleged involvement in the lighting of a bushfire, officers are busily undermining her message. There can be no doubt that the source of most of the material about Brendan Sokaluk, the man charged, has come from police tips and briefings to friendly journalists.

This is not an isolated case. Whenever there is a high profile investigation, you can be certain that the police force involved will leak information for two reasons. First, it creates a climate of guilt around the person arrested, and second, it helps to create an image of a successful investigation.

In the Sokaluk case, police somehow felt the need to link an alleged arson charge with alleged possession of child pornography. The two matters are completely separate, but they help to further tarnish the image of Mr Sokaluk. Then there is the feeding to the media of information and details about Mr Sokaluk’s personality and background, once again done to ensure the media is able to paint Mr Sokaluk in the worst possible light and to imply that the police are removing evil from our streets.

The presumption of innocence is torn to shreds by the police. And of course the media is more than willing to play the game — as it has done before on other recent celebrated occasions, one of which was Mohammed Haneef.

The former Gold Coast doctor was charged in 2007 with a terrorism offence after a high-profile arrest. The Queensland and Federal Police propaganda machines went into overdrive, leaking damaging and, in many cases, misleading material about Haneef, his family and personal circumstances.

There was even a notorious front page story showing Haneef and his family standing in front of a Gold Coast apartment, with the story falsely alleging Haneef was planning to bomb the building. Fortunately, Haneef’s legal team lead by Stephen Keim SC and Peter Russo fought back and released to The Australian one of Haneef’s records of interview with the police, which put a very different light on the case.

It is not only in Australia that the unethical alliance between the police and media in high profile cases operates. In the UK, a Parliamentary Committee is looking at this very issue now. And as Keith Vaz, a Labour MP told the BBC on 18 January:

While it may not always be illegal for police to leak to the media it is certainly wrong and can be very damaging to an investigation or to an innocent individual — remember we are talking often about people who have not been charged with any crime or wrongdoing. Almost as important, it damages the reputation and integrity of the police themselves.

But it is not only the police who leak damaging — and sometimes untested and unsubstantiated — allegations in high profile cases. Government media machines are also happy to play this game, particularly if politicians play sheriff with tough talking rhetoric about how they will ensure the culprits are found and put away forever.