Soon after the Sydney siege began featuring live in the media, a photo of a cuffed ‘terrorist suspect’ – his face clearly visible – was circulated on social media. The image was picked up by the mainstream press and published online. The only problem was that the person depicted had nothing to do with the siege.

Emotions run high following acts of terrorism. The threat of revenge attacks on a ‘terrorist’ is real. If the police had not quickly denied that the man was related to the siege, his image would have been shared on social media until someone identified him. His name and other identifying details would have been deduced and plastered all over the web. He and his family may have been subjected to abuse and threats of violence.

This isn’t paranoid fear-mongering. It’s happened before. After the Boston marathon bombing in 2013, images of the crowd were collectively pored over on social media, en masse. Before the real terrorists were apprehended, several ‘suspects’ were publically identified – convicted by such ‘evidence’ as the fact they carried a backpack or were brown. The New Statesman referred to it as a ‘racist Where’s Wally’. The mainstream media picked up the rumours and it descended into a frenzied witch-hunt with the erroneously accused men’s families being dragged into the mire. It was so vicious that Reddit later apologised.

In the aftermath, a new term was coined: crowd-sleuthing. A portmanteau of crowd-sourcing and sleuthing, it refers to groups of people collectively mobilising online to attempt to solve a mystery.  It is different to crowd-sourced intelligence gathering, which can be helpful. Crowd-sleuths go one step further and try and solve the crimes. They insert themselves into the narrative.

Crowd-sleuthing can be far less high profile. It is the blurry photo of a man circulated on Facebook: This man stole my friend’s dog! Do you know him? Please share!

The day of the Sydney siege, someone I went to kindergarten with found me by posting a message with my name, my family’s names and where I was born on – of all places! – a NZ speed-camera spotting page on Facebook. Within ten minutes, the status had been shared and liked. A distant relative of a friend messaged my old pal. A very distant relative of a very distant relative tagged my father in the post. My kinder-pal then found me in my dad’s friends. The process took 32 minutes.

It was unnerving to see how fast people can be located. And on a speed-camera page! When did everyone get so damn helpful? What if I didn’t want to be found?

There is no doubt that crowd-sleuths are motivated by a sense of duty and, perhaps, more than a little boredom. It is seductive to ‘help’ especially with such a noble cause as Find a Terrorist.

But crowd-sleuthing is not solely motivated by altruism.  There is an aspect of it that is simply about craving the excitement of a challenge – the thrill of solving a puzzle.

I saw screenshots of messages about me. The words were electric with excitement: they knew the answer! They had solved the riddle! The human element had been removed. As we see when people leave vicious remarks online – things that they would never say to someone’s face! – it is easy to forget the real life implications of online actions.

For instance, how did crowd-sleuths know that my old pal was actually my old pal? I could have escaped domestic violence and he could have been my abusive ex-husband trying to find me under a new guise. What if the man didn’t steal a dog and was actually being cyber-bullied? What if the brown guy with a backpack is just a brown guy with a backpack?

We don’t know because no-one is stopping to ask. No-one is gathering evidence and verifying the stories – whether it is establishing the guilt of a ‘terrorist’ or ensuring a ‘missing person’ isn’t actually in witness protection — before they publicly discuss, accuse, research, speculate, post and disseminate.  We just take stories at face(book) value and, as the narrative moves around, like a tornado, it shifts shape and gathers weight: a name, an address, photos off Facebook and Flickr, the names and addresses of family members.

And, in their desperation to scoop the story, the mainstream media aren’t verifying legitimacy either – they’re just grabbing the story and charging forward.  It is shoot-now-ask-questions-later mob mentality.  Instead of the power of the crowd, we have groupspeak.

Get used to it, says the NY Times. Our media today is a ‘tremendously messy’ and often ‘damaging’ interaction between mainstream media, online media and ‘thousands of individuals participating on their own in the gathering and assembling and disseminating of information’. And as it is a process that is ‘constantly evolving’, it’s going to be some time before the rules are ‘codified.’

Luckily for the cuffed man in Sydney, the police quickly denied that he was involved in the siege. But – as we wait for the rules to be determined – what about next time?