This is so completely expected. Anybody who knows the government, knows that they are ALL on network mail servers and the data is backed up all the time. They also have a good reason to believe that like many of the senior government officials of this administration, Lerner used personal and private email accounts to do things she knew damned well were against the law.
Nothing is ever really lost in the infoweb. We always have the endless resources of the NSA saving our data for us.