A group of western investors that bought the final set of Yukos assets, which included Dutch unit Yukos Finance BV, approached the oil group’s former management to obtain assurances about the assets just days before the bankruptcy auction, former Yukos management said.

“We’ve made it clear for the past several weeks that this auction is totally illegal,” said Bruce Misamore, Yukos’s former chief financial officer and former director of Yukos Finance BV.