What has whipped up suspicion is the revelation that Nicholas Biwott, a former cabinet minister, was on the same flight as Muliro.
Oginga Odinga, interim chairman of Ford, has asked who was behind the organisation of a press conference six hours after Muliro died which was addressed by Arthur Obel, Muliro's personal doctor, and senior police officers.
Dr Obel said that Muliro was suffering from a heart condition and he signed a death certificate indicating Muliro died of natural causes (cardiac arrest). He has been summoned to answer charges relating to an alleged violation of the medical ethical code.
Perhaps the murkiest aspect of the affair so far concerns the failure to date to carry out any post-mortem examination, although Muliro's widow, Marcia, is reported to be opposed to any autopsy, because she does not want her husband's body to be 'cut'.
Dr Obel has reacted angrily to the allegations about his conduct. 'My position is that I will not be a sacrifical lamb on a political platform,' he said.
Mr Biwott said he met Muliro at Heathrow airport prior to departure, and Muliro initiated a 'friendly chat'. They boarded the aircraft separately and he never met him again.