A second lawmaker with Kenya's opposition party has been shot dead in what police are describing as a crime of passion. As Nick Wadhams reports from Nairobi, the slaying has already sparked new protests and could add to the post-election chaos sweeping the country.

The death of David Too led political leaders from the government and the opposition to postpone negotiations on ending the post-election crisis. Former U.N. Secretary-General Kofi Annan, who is mediating the talks, said they would resume on Friday.

Later in the day, Mr. Annan's successor, Secretary-General Ban Ki-moon, announced he would fly to Nairobi on Friday to help Mr. Annan quell the crisis.

Police say Too was shot Thursday by a policeman who was jealous that Too was having an affair with his girlfriend, also a police officer. According to the police, Too had picked up the woman at the police station in the Rift Valley city of Eldoret and was shot and killed after the other officer followed them to nearby hotel.

Too died on the way to the hospital. Kenyan media later reported that the woman, identified as Eunice Chepkwony, died of her wounds as well. The police say they have arrested officer Andrew Maoche in the killing.

Raila Odinga and other members of his opposition Orange Democratic Movement have rejected the police explanation of Too's murder and say it was a government attempt to reduce the number of ODM lawmakers in parliament.

"How do they get the information to back up these kinds of claims? It is really suspicious that any time a killing of this nature happens, the police have a ready answer," Ababu Namwamba, a lawyer and ODM lawmaker. "That in itself raises very serious suspicions that indeed this is part of a wider scheme to eliminate the leadership of the opposition in this country."

The death came after another ODM lawmaker, Mugabe Were, was shot and killed as he approached his house on Monday night. Mr. Odinga called Were's killing a political assassination and the slaying sparked a day of protest in Nairobi's slums and in western Kenya.

In the opposition stronghold of Kisumu, young people burned tires and set up roadblocks, protesting the latest killing.

Kenyan government spokesman Alfred Mutua says he believes the opposition claims of conspiracy will only whip up more tension in Kenya. He backs the police version of the slaying and says there is no evidence that Too's murder was politically motivated.

"They are just overreacting," said Mutua. "I don't want to speak about it. It's very clear what the police have said. I don't think they care about peace and security in this country, because otherwise they would not be saying some of these things."

Some 850 people have been killed and more than 250,000 have fled their homes since allegations of fraud surrounding the December 27 vote, which was won by President Kibaki, sparked violence across the country.

The violence has since devolved into ethnic attacks, chiefly between the Kikuyus who support Mr. Kibaki and the Luo, Luhya and Kalenjin who back Mr. Odinga.