Illustration: Matt Golding. As well as tagging images, among Dr Kowalick's greatests concerns is that new facial recognition software and biometrics will jeopardise the back-story of witnesses living under new names and identities. "Their identity in a new name cannot be protected from Facebook, Instagram and other social networking mediums. If the participant had a presence in the old name, their new name and subsequently their location could be discovered through a chance photograph being posted online and both instances of the person's photograph being matched up," he said. The result is difficulty hiding participants in new communities because the chances that the participant or a family member will have been active on social media are growing. Criminal syndicates have a lot to lose and will no doubt go to great lengths to find those who are or will give evidence against them,he said. Dr Kowalick has published the report – his PhD thesis – and intends to to take his findings and proposals for a streamlined national program to the nation's attorneys-general in the new year. However the AFP said as a matter of standard practice, they do not discuss witness protection related matters.

Professor Nick O'Brien, head of the Australian Graduate School of Policing at Charles Sturt University and ex New Scotland Yard, who works closely with state and federal police and agencies, said the issue of inadvertent identification is on the "radar of Australian authorities". The AFP, in their 2014-2015 annual report, said that their measure of key performance indicators of witness protection is that there are "fewer than four avoidable incidents per 5000 protection hours". There were no incidents related to the NWPP during the year. The AFP ran 31 witness protection operations involving 61 people at a cost of $712,565.61. Although it did report that the Commonwealth Ombudsman finalised an investigation into a complaint about the program, the nature of the complaint was not revealed, nor was the outcome. In a previous study conducted with former AFP Commissioner Mick Keelty, Professor O'Brien has already found that social media may compromise undercover police work in the same way it poses a threat to witnesses. In Western Australia, a report to State Parliament said there were no breaches of witness safety, however there were several breaches by witnesses – but they did not result in arrests or incarceration. It said 21 people were assessed to join the program. It also revealed eight males and 13 females were being protected at a running cost of $368.999.

In South Australia, a report to Parliament said they had files relating to 121 people and during the past year three people were terminated from the program and one person asked to be removed. In Queensland, where witness protection is run by the Crime and Misconduct Commission, there were 90 applications for protection and 42 people entered the program. Since its inception in 1987, more than 1690 people have been protected. The CMC report acknowledges that "our results are difficult to compare with the data of counterpart agencies elsewhere in Australasia, as that information is not publicly available." Dr Kowalick has recommend that further research to identify solutions for the vulnerability the social media threat represents to witnesses. But Professor Brian Lovell, from the University of Queensland's School of Information Technology, said that no matter how hard you try, you cannot be guaranteed that your previous social posts have been erased. "If your life depends on your identity being secret it can be very dangerous.

"It is very hard to delete all traces of a previous life," he said. "And if you don't have a social media profile – people are also suspicious." How tagging works: Tagging means that after you upload a picture of your friends to social media like Facebook, there is an option to click on their faces and type their names, identifying who is in the image. Tagging makes it very easy to find every photo featuring of that person through recognition software. Every time you are tagged in a photo on Facebook, you will be sent a message. You can't stop the tagging but you can untag yourself and request it be removed.