"They know who is responsible. We know who is responsible. The question is, is the Serbian government going to lift the curtain of silence surrounding this case?" said Barry.
Barry said the top person responsible is the training camp commander, Goran "Guri" Radosavljevic, who has political ties to the ruling party.
Rep. Tim Bishop (D-Southampton) introduced a resolution last year saying the Serbian government should make the case a top priority.
It also says the brothers' case should remain a "significant factor" in U.S. and Serbian relations.