The fate of Syrian-born Mustafa Setmariam Nasar, aka Abu Musab al-Suri, aka the 'red-headed terrorist', remains unclear. Back when the Syrian Arab Spring uprising began a few years ago, press reports suggested Assad had him in lockup and would release him if the United States didn't stop meddling or calling for regime change.
After that threat failed to stop the uprising it was reported that he was released. Then recently it was reported again he was still incarcerated.
Why is he significant? In the past few days images have come out of Bin Laden's Tora Bora hideout, in which Setmariam is seen beside UBL many times. National Journal's Michael Hirsh once called him "the next bin Laden".
Daily Mail even mentions his theory of small jihad on a large scale, something which seems to be in its infancy all around the world now. He's also reported to have been behind the planning of the UK subway/bus attacks and perhaps the Madrid train bombings back in 2004. So it might be helpful to know where he is.
By the way, the (other) western looking dude sitting to UBL's left is Gwynne Roberts, a British documentary filmmaker who wanted to do a story about the sheikh before he was well known.
Regarding another dangerous terrorist, Adnan El-Shukrijumah has disappeared off the State Department's Rewards for Justice site but remains on the FBI's Most-Wanted Terrorists site. Not sure if that's significant or just bureaucracy in action.