Just unscrambled the pic myself
I downloaded and played with the image in Photoshop, just to see whether or not the descrambling was all tht difficult. I suspected it would be; my first suspicion was that the perpetrator, knowing he was creating photographic evidence of crimes, would at the very least use multiple passes of the filters he used to obscre his face, possibly with different selections or at different levels.
As it turns out, he didn't.
Anyone with Photoshop can do this, though getting results as good as Interpol's takes some precise work and jiggery. Still, in about five minutes (and working from the image posted on El Reg), I was able to get results almost as good as Interpol's.
If anyone cares about the technical details, he used the built-in Photoshop "Twirl" filter. You can undo it yourself in Photoshop. First, make a selection of the distorted part of the image. Use the oval marquee tool; I found it easiest to start from the center part of the twirl (the center of the eye) and expand the marquee outward rather than trying to freehand the selection. Bring the marquee right out to the outer edge of the distortion effect; I used the point at which the horizontal gold stripe of the wall pattern behind him begins to distort. The affected area is almost, but not quite, a perfect circle.
Then run the Twirl filter. Start with a setting of -999 degrees; he ran it originally at maximum effect. If you see asymmetric distortion of his face, your selection wasn't quite right; rejigger your selection a little bit, rinse, and repeat. You'll know you got your selection right on the money when his face magically appears out of the swirl.