To echo Bjorn's post, somewhat. It sound to me like you probably had a colony that went queenless for some reason, maybe it is diseased, or somehow became weak enough for neighboring colonies to start robbing it.
Very few dead colonies are CCD related. Of the 30% mortality last year, only 10 or those 30% were CCD related or suspect, according to the Apiary Inspectors of America. What caused the other 20%?
Early CCD reports were that the CCD colonies didn't get robbed. Take that into consideration too.
Mark Berninghausen "To float, upheld, as salt water would hold you, once you dared." Denise Levertov, poet