Until recently [was / has been ] leading one branch of a major and ongoing corruption investigation before being removed from his post

The prosecutor, who until recently ............ leading one branch of a major and ongoing corruption investigation before being removed from his post, has submitted a legal challenge to his reassignment to the Bakirköy Courthouse.

A) was
B) has been

The prosecutor was removed from his post. Therefore the answer is, I think, A) was. Is "has been" OK too?