By Guy De Launey
BBC News, Phnom Penh
Khem Mgoun is one of the most senior Khmer Rouge figures to face justice
Khem Ngoun had swaggered into Phnom Penh's Municipal Court as if he were considering buying the place.
He stood slightly apart from the other four defendants and held a fuchsia-coloured hand towel to mop his brow.
Even his blue, prison-issue pyjamas were of a different design and a better fit than those his former Khmer Rouge colleagues were wearing.
His initial appearance at the court earlier this month suggested that Khem Ngoun still saw himself as a powerful man, one who deserved more respect than to be charged with kidnapping and murder.
But his 20-year sentence confirms that former Khmer Rouge leaders should no longer feel safe from prosecution.
It is not the first time that a former Khmer Rouge member has been found guilty in connection with the organisation's activities in the 1990s.
Until only last year, it seemed the past would not trouble Khem Ngoun
But Khem Ngoun was very close to the top of the hierarchy before the Khmer Rouge disbanded 10 years ago. He was the right-hand man to the military chief Ta Mok, and played a part in the internal coup which ousted the long-time leader, Pol Pot.
When the Khmer Rouge disbanded in 1998, an agreement with the government meant that many former members took high-ranking posts in civilian life or the military.
Khem Ngoun became a brigadier general in the Cambodian army, and lived unmolested until his arrest last year.
The authorities had long shown little enthusiasm for charging senior Khmer Rouge figures. The memories of a three-decade-long civil war were too fresh, and the organisation's surrender too recent, to consider risking stirring up trouble again.
But at last the mood has changed, and Khmer Rouge leaders are being called to account.
Five of them are being held in custody at a United Nations-backed tribunal, charged with crimes against humanity.
Progress towards trials there has sometimes seemed painfully slow. But Khem Ngoun's conviction has raised hopes that justice may no longer be so elusive.
He was found to be responsible for giving the order to shoot Chris Howes, days after he was kidnapped while leading a mine-clearance operation near the town of Siem Reap 12 years ago.
The court also ordered Khem Ngoun to pay $10,000 (£) in compensation to the widow of Chris Howes's Cambodian interpreter, Houn Hourth.
Their former employer, the Mines Advisory Group (Mag), was delighted with the verdict.
"I think it's very important for the Cambodian justice system in as much as it's proof that justice can be done despite lengthy periods between crime and court," said the director of Mag's Cambodian office, Rupert Leighton.
Streets and schools are now named after Christopher Howes
"I think it's also a good signal for the tribunal, and a healthy sign for the justice system in Cambodia."
It is also, perhaps, a fitting tribute to two men who sacrificed their own lives to save their colleagues.
The Khmer Rouge unit which ambushed the Mag team led by Chris Howes gave him the chance to walk free, if he returned to his office for ransom money. Fearing for his workmates' safety, he refused.
While more than 20 de-miners were later released or escaped, Chris Howes and Houn Hourth were taken to the Khmer Rouge stronghold of Anlong Veng, where Khem Ngoun decided their fate.
It took more than two years, and the intervention of a team of investigators from Scotland Yard, before their deaths were confirmed.
One of Phnom Penh's smartest streets was re-named in honour of Chris Howes. It serves as a reminder of the bravery of the mine clearance experts who have risked their own lives to make Cambodia a safer place.