"The purpose of this killing is to reduce the ODM majority."'Crime of passion'
According to a police commander in Nairobi, the capital, the killing appeared to be linked to a romantic dispute.
"He was with a girl who is a police officer. He was shot by another policeman believed to be her boyfriend," he said.
Earlier this week, Melitus Were, another opposition legislator was shot dead outside the gate of his Nairobi home, in a murder that triggered rioting and ethnic killings.
The ODM said Were's killing was a "political assassination", although police said they were treating it as "murder".
Too was the legislator for the Ainamoi constituency in the Rift Valley.Rival talks
With the death toll from the post-election violence nearing 1,000 and close to 300,000 people displaced, representatives of Mwai Kibaki, the president, and Raila Odinga, the opposition leader who accuses Kibaki of rigging the December election, met on Thursday for the first time together in Nairobi with Kofi Annan, the former UN chief.
Kibaki attended an African Union (AU) summit in neighbouring Ethiopia, despite efforts by the ODM to get the AU to exclude him.
The ODM warned that Kibaki's presence in the ranks of the heads of state would amount to a recognition of his election, despite local and international concerns over flaws in the vote count of December 27 polls.
Protests against Kibaki's re-election quickly descended into ethnic violence amid longstanding tribal and economic tensions. 'Not ethnic cleansing'
|The unrest was triggered by a poll dispute|
but has now become an ethnic conflict AFP]
Meanwhile, the US backed away from comments by its most senior African envoy that Kenya's post-election violence is "clear ethnic cleansing".
Sean McCormack, a US state department spokesman, said the views expressed by Jendayi Frazer, the assistant secretary of state for African affairs, were not those of the government.
"She made some comments based on her firsthand assessment from a trip several weeks ago," he said on Wednesday.
"She said what she said. I am going to stick to what I said."