Board Thread:General Discussion/@comment-25938300-20160530130915/@comment-5538792-20160606145047

Who says S.H.I.E.L.D. knew that Bucky was the killer? Zola revealed it to Cap and Black Widow in The Winter Soldier, so it's likely that only the involved HYDRA members knew about it. Bucky made it look like an accident, after all.