How could a previously unknown group pull off such highly organized and deadly attacks? Deccan Mujahedeen—“Deccan” is an area of India; “Mujahedeen” are Muslims participating in jihad—has claimed responsibility for the Mumbai attacks, but terrorism experts say they doubt such an unknown group could have been behind them. Instead they are pointing to the Indian Mujahedeen, a radical Islamist group that has claimed responsibility for other attacks this year. The group sent an email in September warning of an impending attack on Mumbai and threatening a senior police official. The head of Mumbai’s anti-terror squad was among the dead Wednesday night.