How did the bloody Baron killed Helena Ravenclaw?
He was sent by Rowena Ravenclaw to find Helena in Albania, but Helena refused to return with him and so he killed her in a rage. When he realised what he had done, the Baron stabbed himself with the same knife and died by suicide.
Who destroyed Rowena Ravenclaw diadem?
Vincent CrabbeVincent Crabbe inadvertently destroys Rowena Ravenclaw’s diadem in the Room of Requirement. It is stabbed with a basilisk fang and then kicked into a Fiendfyre.