Why is it so difficult to prosecute returning fighters?

As the terrorist organisation Islamic State (IS) suffers further losses in Syria and Iraq, increasing numbers of Australians fighting in those conflicts will likely seek to return home. Around 100 Australians are fighting with IS in the Middle East, and around 40 have already returned.

Reports that only two of these 40 fighters have been prosecuted on return are concerning. This suggests there are serious deficiencies in the government’s ability to successfully prosecute fighters returning from these foreign war zones.

This is despite recent changes to the law in which the federal parliament strengthened many foreign incursion offences. It is an offence for a person to enter a foreign country with intent to engage in hostile activity, or even to prepare to do so. Both these offences are punishable by life imprisonment.

So what makes it so difficult to prosecute returning foreign fighters? And what other options are available?

Foreign evidence

When police investigate a terrorism plot within Australia, they can collect a wide range of evidence to later prove terrorism offences in the courtroom.

Depending on what an investigation uncovers, this evidence can include weapons and ammunition, extremist material stored on CDs and computer hard drives, and bomb-making materials.

A significant category of evidence used in terrorism trials is transcripts of conversations that Australian police or intelligence agencies have covertly recorded. The statements of witnesses, including undercover intelligence officers, can also be used to prove a person’s guilt.

In theory, similar kinds of evidence could be obtained from overseas and used in an Australian courtroom. Amendments made in 2014 to the Foreign Evidence Act allow for foreign evidence to be adduced in terrorism trials, provided the evidence would not have a “substantial adverse” impact on the ability of the accused to receive a fair trial.

Foreign evidence will not be admissible if the judge is satisfied it was obtained through torture or duress.In reality, collecting evidence in a foreign war zone is near impossible. Ordinarily, evidence could be provided to the Australian government by a foreign authority, collected through a joint operation with a foreign police service, or recorded on surveillance devices with the consent of an appropriate foreign official.

Syria and Iraq remain in a serious state of armed conflict and lack the governance structures for these to be realistic possibilities.

Another obstacle is that much of the information about Australians fighting overseas comes from foreign intelligence services, including the UK’s MI6 and the US Central Intelligence Agency. Conditions imposed on the sharing of this material mean the vast majority of it cannot be used as evidence in case it is exposed in open court.

Witness statements could be used to support claims of Australians engaging in terrorism overseas, but unless these are from reliable eyewitnesses, much of this could be excluded as hearsay.

In short, in the absence of an admission, confession or guilty plea, it is likely to prove extremely difficult to prosecute fighters returning from Syria and Iraq.

Declared area offence

The most viable option would be to prosecute a returning foreign fighter for entering or remaining in a declared area. This offence, punishable by ten years’ imprisonment, was introduced in 2014. It does not require proof that an individual engaged in hostile activity. It merely requires that the person was present in an area that the foreign minister has declared a “no-go” zone.

Currently, the only declared areas are al-Raqqa province in Syria and the city of Mosul in Iraq. It may still be very difficult to prove that a fighter was in one of these areas. It is possible that video evidence could provide proof, if somebody happened to film a fighter in a recognisable location and the footage was posted online or could otherwise be reliably obtained.

What other options are available?

The difficulties in prosecuting returning foreign fighters does not mean Australia faces a “deluge” of foreign fighters “roaming free” without consequence. Many more may still be killed overseas, and others may choose not to return.

At a minimum, those who do return will be subject to close scrutiny and surveillance by ASIO and the Australian Federal Police. If their behaviour becomes criminal – and there is a long list of broad terrorism offences – prosecution could become viable.

Returning foreign fighters may also be subject to control orders. These court-imposed orders enforce requirements such as abiding by a curfew, reporting regularly to police, and wearing an electronic monitoring bracelet.

A control order does not require proof that a person has committed a criminal offence. If a person breaches the conditions of an order, they will face five years in prison.

Australian police and intelligence agencies will explore these and other possibilities to ensure returning foreign fighters do not cause harm to the community. It is possible that prosecution may still be the intended strategy in many cases. But it takes time to build a solid case given the difficulties of gathering evidence.

Even so, the apparent challenges with prosecution suggest that returning fighters will pose a difficult security challenge for Australia in coming years. Surveillance of large numbers of returning fighters will be expensive and require significant resources, so this is not a realistic long-term solution.

These difficulties also demonstrate the limits in continually responding to terrorism with ever-stronger counter-terrorism powers. Many of the laws now proving difficult to prosecute were framed by the Abbott government as an urgent and necessary response to terrorism.