rat line
n.— «The former CIC colonel said hundreds of Nazis were brought out of Germany by the same route and “everybody that went through the Rat Line was personally accompanied to the ship by a member of our organization.”» —“U.S. agents felt ‘no great pangs’ after helping Barbie flee Europe” Globe and Mail (Toronto, Can.) July 5, 1983. (source: Double-Tongued Dictionary)