On Monday, ISIS’s elusive leader Abu Bakr Al Baghdadi re-emerged with an audio message directed at supporters of the terrorist group .

Followers of Baghdadi, who is said to be badly injured, reacted on social media from across the world as they posted images of support. But at a time when it is nearly impossible not to leave some sort of online footprint, experts in open-source intelligence set about geolocating where the images were taken.

First image I found can be geolocated to دوار المحراب in Idlib City at 35.9329, 36.6410.https://t.co/ldj7xGalAv pic.twitter.com/cg8x5Wgzon — Nick Waters (@N_Waters89) September 16, 2019

Nick Waters, a senior investigator at Bellingcat, was initially able to identify a number of sites in Syria and Turkey. This included the last rebel-held Syrian territory of Idlib, a park in Konya, Turkey and what appeared to be Al Bab, a city in Aleppo Governate. Unsurprisingly, Syria, Iraq and Turkey featured prominently.

As the account published its revelations, other Twitter users were inspired to look into more of the posts and pinpoint the locations of those pledging allegiance to the terrorist leader.

Pretty sure the Al Bab one is in vicinity of 36.369542, 37.500700. On the landscape image I added the 2 antenna as blue triangles. I suspect the minaret that can be seen is at 36.37427, 37.50437: the orientation with the dome seem to fit (H/T @JakeGodin)https://t.co/OTVpJXv5sX pic.twitter.com/H7WhToqFgf — Nick Waters (@N_Waters89) September 16, 2019

Tomasz Rolbiecki, another open-source intelligence expert, tracked down a photograph to Homs in Syria, near the Khalid ibn Walid Mosque.

Found location of one of the photos from Homs - near Khalid ibn Walid mosque (approx. 34.7368031, 36.7151445)https://t.co/ulILLY9jfY pic.twitter.com/dvpcmu4tcW — Tomasz Rolbiecki (@TomaszRolbiecki) September 16, 2019

The images were part of a wider series of messages of support posted by ISIS followers that were tracked online. A Twitter user who calls himself Caki found a video of an ISIS supporter standing not far from a Turkish base in the vicinity of Syria’s Al Bab.

Video ISIS member nr Turkish base just outside al-bab pic.twitter.com/4rZmVbI8Nl — Caki (@_Caki__) September 16, 2019

ISIS members also seemingly showed support from a number of areas in Iraqi Kurdistan and Raqqa, the former capital of the terrorist group's so-called caliphate. They also came from across Europe, the Middle East and North Africa, with one message claiming to have come from as far away as Brazil.

As pointed out by Bellingcat in 2016, when ISIS loyalists acted in a similar way by displaying public messages of support, in certain cases it is possible to track down the location of supporters who post online messages.

Twitter users were able to pinpoint one supporter to a street in Munster, Germany, and another to the Bruce Grove railway station in North London.

"Overall, the ISIS social media campaign backfired spectacularly, likely revealing information about multiple ISIS supporters in major European cities, including their residential locations and, perhaps with CCTV cameras, their identities," Bellingcat wrote at the time.