Why Belgian police turned to social media for help

Belgian police turned to social media in the early hours of Wednesday morning (23.03.2016) as they hunted the suspects behind twin bomb attacks at Brussels' Zaventem airport.

Each of the tweets reads: "#TERRORISM Who recognizes this man?"

The first two men are thought to have died in the suicide attacks at the airport.

The final tweet features Najim Laachraoui himself, considered the only living suspect.

Just one day earlier - March 21, a Monday, at 6 p.m. (14 hours before the attacks) - the same Belgian police handle had tweeted two images of this same man, along with the hashtag #TERRORISME:

This Belgian Twitter campaign roughly translates to "Wanted Poster." The handle @police_temoin means "Police Witness." It is operated by federal and local police in Belgium, and it's part of an international trend that's leveraging social media users in an attempt to catch wanted criminals.

#WantedWednesday

Like Belgium's @police_temoin handle, police departments throughout the world are now operating Twitter, Facebook and even Instagram accounts in the hope that social media users will recognize wanted suspects whose pictures are posted online.

In the English-speaking world, many of these departments have settled upon a hashtag - #WantedWednesday - which has united the local, regional and national police bureaus into something of a common campaign.

Every Wednesday, from the US to Canada to the UK and elsewhere, social media users who follow these accounts are treated to a pictorial update on the most wanted suspects in their area:

Many police departments are celebrating the spread of the campaign. One police spokesperson for a county department in the US state of Maryland told a local news branch: "I'm glad to know that we're beyond the conversation of police departments having Facebook and Twitter and Instagram. We're way beyond that."

Part of the reason these campaigns have spread rapidly is that they're working.

Beyond the tips from social media users, the publication of these images - and their potential infinite reach - has caused many criminals to turn themselves in before they're discovered.

And those tweets are just a sample from March 2016.

International teamwork

In Belgium, the team behind the Avis de Recherche Twitter posts similar wanted posters.

Many of their tweets include pictures of known suspects, security camera footage of unidentified suspects in the act of committing a crime or announcements of captured individuals.

(This last tweet is a reference to the capture of Paris attacker Salah Abdeslam).

The more recent anti-terror campaign is merely an evolution on these online "wanted posters," with Belgian police now deploying the hashtag #TERRORISME to make clear the suspect is potentially involved in terror activities.

As details of the March 22 Brussels attacks are revealed, it will be interesting to learn whether there was a connection between the timing of the first tweeted pictures of Najim Laachraoui on March 21 and the bombing that occurred only 14 hours later.

In any case, as the trend accelerates and internationalizes, it implies that online users might be able become something of a collective social media crime-fighting squad - no matter where they are located.

Finally, however, one important caveat:

Online users have been sensationally wrong in the past when trying to identify bombers in high profile cases of terror - namely, in the identity of the Bangkok bomber, of a woman falsely accused of involvement in the November Paris attacks and of the Boston Marathon bomber.