Ex-Khmer Rouge men jailed for Briton's death

• Cambodian army general among four found guilty
• Verdict raises hopes for UN-backed genocide court

Four former Khmer Rouge guerrillas were jailed by a Cambodian court yesterday over the kidnapping and murder of a British mine clearing expert and his interpreter 12 years ago. Three of the accused were sentenced to 20 years imprisonment and a fourth got 10 years for their parts in the killings of the former British army engineer Christopher Howes and Huon Hourth.

The rare convictions of ex-Khmer Rouge fighters appear to reflect a new determination by the government of the prime minister, Hun Sen, that augurs well for the delayed UN-backed genocide tribunal.

Howes, 37, from Backwell, near Bristol, was murdered in the Cambodian jungle days after he was seized along with a 30-strong team from the British-based Mines Advisory Group (Mag) in March 1996. But his fate remained a mystery for two years until Scotland Yard detectives investigating the disappearances found fragments of bone in a fire used to try to destroy the evidence.

The Phnom Penh court heard that three of the accused, including a former senior Khmer Rouge commander who became a Cambodian army brigadier-general, combed the fire's ashes for fragments to show to the communist guerrilla group's army chief, Ta Mok.

The Khmer Rouge's military commander had passed down the order from the leader, Pol Pot, that Howes should be killed on the grounds that foreigners in the country were helping the Cambodian government.

It was only after the final defeat of the Khmer Rouge in 1998 and the defection of most of the guerrillas that it was confirmed Howes had been killed near the 12th century Angkor Wat temple complex. It was another 11 years before the five accused - Khem Ngoun, 59, Loch Mao, 54, Puth Lim, 58, Sin Dorn, 52, and Cheath Chet, 34 - were arrested in the Khmer Rouge stronghold of Anlong Veng and charged.

Yesterday, Howes' sister, Patricia Phillips, said: "Although we have never sought revenge, we are pleased that the murderers have been brought to account."

Ngoun, Ta Mok's chief of staff who became a brigadier-general in the Cambodian army, Mao and Lim, admitted they had been present when Howes was shot dead and burned. But all accused another guerrilla, Nget Rim, who has since died, of firing the fatal shot. They each received 20 years for being part of the murder conspiracy, while Dorn, who played a smaller role early in the kidnapping, was given 10 years. Chet was freed.

The court heard that Howes was given the chance to leave to fetch ransom money for the Mag team, but he chose to remain, a decision that earned him a posthumous Queen's Gallantry Medal.

Most of the Mag team escaped or were freed within a day of the kidnapping, though Howes and Hourth were held and taken towards Anlong Veng. Hourth was killed when he was deemed "no longer necessary" as Ngoun could speak English to Howes.

Five of the most senior surviving Khmer Rouge leaders have been indicted by the separate UN-backed tribunal in an effort to bring to book those responsible for the deaths of up to 1.7 million people in Cambodia's "killing fields" during the regime's four-year reign up until 1979.