Two more suspected members of the ''hole-in-the-roof'' gang were arrested Saturday in the largest cash heist in US history. One suspect, Demetrios Papadakos, is alleged by police to be the mastermind of an operation that stole $11 million from a Sentry Armored Car Courier Dec. 12 . The arrests bring to four the number of people charged in connection with the theft. Federal agents were still looking for at least two others. The money hasn't been found.