The Archives buildings was a new, modern multistory commercial building surrounding by multistory residential buildings. When it collapsed into the hole, some of the surrounding buildings were damaged. The one where the two victims are missing is an older (like more than a 100 years old looking) brick building. When brick buildings collapse, the brick crumbles into sand and small pebbles, filling every possible void. Even the ASC couldn't get in.
The robots were requested this afternoon for the mixed rubble from the houses and the Archives, but it wasn't a good fit. There were small voids but we couldn't stand at the face of the rubble due to safety reasons- and the ASC requires us to be right there. The voids big enough for the larger Extreme, which we could operate from the safe location ~10m away, were shallow and thus didn't require a robot. More notes on how to build better robots.
We're back on site tomorrow- a huge crane is being brought in to do more excavations and more voids may open. It looks like the old fashioned tedious manual rubble removal is the best technology for this job for now.
Lots of pictures but haven't gotten permission to release them yet, here's link to pics from the media and gratuitous coverage ;-) Can't seem to embed the URL so please cut and paste
Local news in English: http://www.thelocal.de/national/20090307-17863.htm