Videos and pictures posted online by terrorists are supposed to be tools of propaganda. But they can also play a crucial role in helping to identify the locations of these militants. The producers of the Web site Bellingcat have dedicated themselves to doing exactly that and recently were able to locate an Iraqi training camp of Islamic State militants. "This stuff really isn't that hard to do once you pick up the basics," Bellingcat-founder Eliot Higgins told WorldViews.

Higgins used to operate under the pseudonym Brown Moses when he started to blog about Syria in 2012. He had never been to a war zone, did not speak Arabic and knew little more about weapons than the average Xbox owner. The reason why he had time to blog was his unemployment as a former finance and admin worker. But Higgins’s analyses of YouTube videos and photos posted from the Syrian frontline won him praise and attention. Higgins, who initially hid behind his pseudonym, decided to reveal his real identity in order to better defend the integrity of his work. It was a watershed moment: A field previously occupied by a few specialists was now open to anyone with interest, rigor and an Internet connection.

Here is how it works.

Higgins and his coworkers examined photos posted on July 21 by a Twitter account associated with Islamic State militants which show the 'class of 2014 martial arts lesson.'

"It was possible to establish the time and direction the camera was facing using the shadows that are visible which narrowed down the location," says Higgins. Other landmarks were widely visible constructions such as the bridge on this photo:

Higgins and his colleagues were able to find a bridge which looked similar in Google Earth.

To be more precise, Higgins used the tool Panoramio which relies on Google Maps to Geo-tag photos. That way, the pictures of tourists can become extremely valuable. By analyzing street lamps and Arabic letters Higgins verified the location of the bridge.

It is not the first time, Bellingcat has used such tools to analyze where pictures were taken. This weekend, the researchers supposedly found the location of American journalist James Foley's execution site in Syria, partly by comparing the shape of hills. The still of the execution video shows several distinct craters:

By using satellite images Higgins believes to have found an area extremely similar to the landscape shown in the execution video. Here are the detailed stills from the video:

And these are the satellite images supposedly showing the same location:

Who is behind this?

Higgins has been doing this for a while and is widely praised for his work. A Guardian profile from 2013 portrayed him as having never been near a war zone. Despite working from his computer and not being an expert on the Middle East, Higgins managed to monitor weapons and find evidence for the use of cluster weapons in Syria making him "perhaps the foremost expert on the munitions used in the [Syrian] war," as the New Yorker put it.

New York Times veteran war reporter CJ Chivers told the Guardian that "many people, whether they admit or not, have been relying on [Higgins's] blog's daily labor to cull the uncountable videos that circulate from the conflict."

And why is he doing it?

After Higgins realized the impact his research had he started a successful crowd-funding campaign, collecting money to start Bellingcat. "Our donors reacted very well. I think a lot of them support Bellingcat because they want the exact type of analysis we've been doing the past weeks," Higgins told WorldViews.

To him, it is important to show "other people how to do this work and get them engaged with doing actual investigations." Consequently, he expects another repercussion: Being tracked down, Islamic State militants might become more cautious about posting their gloating propaganda. Perhaps, says Higgins, they'll be more inclined to make statements "from dingy basements which don't really portray the message of strength they're trying to get across." In a fight where online rhetoric is part of the arsenal, it could be a first step toward silencing Islamic State militants.