Kenyan President Daniel arap Moi and a key aide are suing a former U.S. ambassador for suggesting they were involved in the murder of former foreign minister, Robert Ouko. This is the second time the Moi government has gone to court to silence accusations of role in the murder, which occurred more than 10 years ago.

President Moi and cabinet minister Nicholas Biwott have filed separate libel cases against retired U.S. envoy Smith Hempstone, for implying they participated in Dr. Ouko's murder in 1990.

They are also suing a local book store, the Text Book Centre, for sale and distribution of Mr. Hempstone's autobiography, Rogue Ambassador. In the book, Mr. Hempstone suggests Dr. Ouko was murdered at State House, the residence of the president.

Foreign Minister Ouko was one of Kenya's most promising politicians. He disappeared shortly after returning from a trip to the United States with President Moi in 1990. Three days later, his mutilated, burned body was discovered on a hill behind his home in Koru, near Kisumu in western Kenya.

It was widely reported that President Moi and Dr. Ouko argued after the minister upstaged Mr. Moi at a breakfast meeting with then-U.S. President George Bush.

Mr. Hempstone's writes in Rogue Ambassador that after returning to Kenya, President Moi summoned Dr. Ouko to State House and beat him unconscious. The book goes on to say that Dr. Ouko was later tortured by the members of Kenya's Criminal Investigations Department before Mr. Biwott shot him twice in the head.

In their lawsuits, President Moi and Mr. Biwott say Mr. Hempstone's words portray them as criminals unfit to hold public office. They want an injunction restraining the former ambassador from continuing to publish and sell his book.

Mr. Hempstone served as ambassador to Kenya from 1989 to 1993 and frequently angered the Moi government by siding with opposition calls for an end to one-party rule.

This is not the first time the government has been accused of murdering Dr. Ouko. Many Kenyans began to suspect a cover up when a government pathologist declared that Dr. Ouko had committed suicide.

The Kenyan government invited detectives from Scotland Yard to come and investigate the death of Dr. Ouko, but Nairobi ordered them to return home before they were able to complete their investigation. However, in a preliminary report, the British detectives concluded that Dr Ouko had been murdered after being tortured. Mr. Biwott was arrested as a prime suspect but released for lack of evidence.

One of the Scotland Yard team, Dr. Iain West, a pathologist, went on to write a book that implicated Mr. Biwott in Dr. Ouko's death. Last year, Mr. Biwott sued Dr. West for defamation, charging that the book portrayed him as, in his words, a murderer and most corrupt person.

Mr. Biwott won a record $400,000 in compensation and the book is now banned in Kenya.

The Kenyan government has never released the Scotland Yard report into Dr. Ouko's murder, despite great public demand for it to do so.