New Zealander Rob Hamill has told Cambodia's United Nations-backed war crimes court how he had felt like killing the boss of the prison where his brother was murdered by the Khmer Rouge regime.
Mr Hamill's brother, Kerry, was one of three foreigners killed by the Khmer Rouge after their yacht was blown off course and into Cambodian waters in 1978.
Mr Hamill, an Olympic and transatlantic rower, is testifying at the trial of the jail chief, known simply as Duch, who is accused of overseeing the torture and execution of about 15,000 people.
Mr Hamill told Duch he wanted to smash him in the same way he smashed so many others.
Duch has said the Khmer Rouge used the term "smash" to refer to killing its enemies.
Duch has previously accepted responsibility for running the jail, but insists he did not have a central role in the Khmer Rouge hierarchy.