A group of crowd-funded citizen journalists seem to have located a training camp for the militant group ISIL using only online mapping services and some old-fashioned detective work. Bellingcat , which raised almost £51,000 ($85,000) to do its own unique form of journalism, was founded by Eliot Higgins, who became famous (and was profiled by the New Yorker ) for proving Syria was using chemical weapons from his bedroom in Leicester, England using only images and videos available online. His team includes a mix of bloggers, research analysts, and traditional reporters.

Bellingcat has explained in detail how it found the exact location of a training camp. First, using stills from videos showing the graduation of an ISIL class earlier this year, the team identified a large river and several bridges in the background, which it identified as the Tigris in Mosul, Iraq, the city that ISIL took in June and have been wreaking havoc in since . The group used Google Earth to make the identification.

To identify exactly which building, Bellingcat used Flash Earth , a more up-to-date service that uses Microsoft’s Bing Maps to see where along the river the building is.

“In the entire area there’s only one possible location that matches, on the north side of the river, with the camera pointing south,” the team said. “It also appears the martial arts lessons were photographed in the same area, with the bridge running over the road visible, and the trees on the right.”

The team also used Panoramio , a service that takes the location metadata on photographs and puts them on a Google Map. Using a single photo, Bellingcat noticed that the Arabic writing on a bridge in the corner of the picture, as well as the placement of the street lights.

It also used old photos on Google Maps against the Panoramio pictures to determine that the buildings the jihadists are marching in front of are new, and that they must have marched 2.9 km (1.8 miles).

The whole process to pinpoint the training camp is impressive—and what is more impressive is that you can do it too. Bellingcat has a series of guides on how to geolocate photos and images. As Higgins explains his mission on Kickstarter: