Why did he cut off their hands? New Jersey Attorney General Jeffrey S. Chiesa said: "We allege that the defendant was ruthless and calculating in the manner in which he carried out the killings and attempted to prevent identification of the victims by cutting off their heads and hands before burying their bodies."

That may be, but the story below notes that the victims were Coptic Christians, and "privately some wonder if it had something to do with the victims' religion."
[link to www.jihadwatch.org]