The blogger, more commonly known by his internet pseudonym Guido Fawkes, accused Sunday Mirror editor, who sits on the PCC, of personally authorising her staff to obtain information by hacking and blagging.
Weaver said she was not aware of phone hacking being used under her editorship in earlier evidence to the Inquiry, but Staines alleged two journalists had told him that she had personally authorised them to hack, and that "she knows all the bad things that have gone under her rule".
The right-of-centre Guido Fawkes blog has a reputation for baiting the political and media establishment and is run offshore, which places it beyond the British legislative system and media regulators. Mr Staines's comments were also covered by privilege, so he cannot be sued.
He also claimed that the Daily Telegraph reporter Gordon Rayner – responsible for a 2009 story that revealed Staines's real identity and described him as "the journalistic equivalent of an arsonist" – of being a client of convicted private detective Steve Whittamore.