The director of the Central Intelligence Agency, John Brennan, issued an extraordinary apology to leaders of the US Senate intelligence committee on Thursday, conceding that the agency employees spied on committee staff and reversing months of furious and public denials. Brennan acknowledged that an internal investigation had found agency security personnel transgressed a firewall set up on a CIA network, called RDINet, which allowed Senate committee investigators to review agency documents for their landmark inquiry into CIA torture."