Bank guarantee night is the ultimate whodunnit

Josephine Citizen was murdered on the night of September 29, 2008, in government buildings. The murder weapon was a sharp-edged bank guarantee. Present were a splendid cast of suspects, including fatcat bankers, clueless politiicians and inept senior civil servants. Whodunnit?
Was it Professor Cowen, leader of the boisterous cult known as Fianna Fáil? Did Dr Lenihan try to save Josephine only to be repelled by feckless bankers? Had anybody drink taken? Were the civil servants awake when the deed was done? Does any of it really matter?