The killing has generated huge controversy

Chief whip Norman Nyagah told the BBC's Network Africa programme that he had in fact tried to save the life of Crispin Mbai.

The allegations were made in parliament on Wednesday by another MP, Peter Owidi, sparking angry exchanges between MPs.

Politicians from both the ruling National Rainbow Coalition (Narc) and the opposition have said that Mr Mbai's killing was a political assassination meant to derail the constitution review process.

I stood surety for him in hospital for 300,000 shillings ($3,815) when they refused to admit him Norman Nyagah

Three people have been charged in connection with the murder.

A newspaper editor and a police detective have also been charged with theft of a videotaped statement to the police after the Sunday Standard paper published an alleged confession from one of the suspects.

'Good neighbour'

"My name is being touted because of my proximity to the head of state [Mwai Kibaki]," Mr Nyagah said.

He said that he lives near Mr Mbai and when he heard the gunshots he immediately rushed to his aid.

"I stood surety for him in hospital for 300,000 shillings ($3,815) when they refused to admit him. I called the minister for health, Honourable Charity Ngilu to speak to the hospital to get them to admit the person," said the chief whip.