Mumbai siege suspect a US double agent?

RussiaToday
December 22, 2009
Indian authorities suspect David Headley, the Chicago man arrested and charged by the U.S. in connection with the Mumbai terrorist seige that killed more than 150 people last year, could have
been a CIA double agent. Is there credible evidence to support this theory? Could U.S. intelligence have known about plans for the Mumbai attack? And what does this mean to relations between New Delhi and Washington D.C.?