He was also the person who leaked the whole MtGox "hack" to the public. Mark approached him and the twins before he went public. They knew about this problem before anyone else knew about this, and they had time to get their money out before the whole thing collapsed. < Mby not from MtGox, but out of Bitcoin >

Mark wanted to keep it quite, and were looking for people to "invest" coins to keep it alive, until he would be able to collect enough coins to hide the loses, but Roger and the twins were not buying into that, because the losses were simply to big.