Former champion New Zealand rower Rob Hamill has appealed for people in Australia's Northern Territory to help him piece together some of the last days of his brother's life there, before he set off in a yacht and was brutally murdered by the Khmer Rouge.
Kerry Hamill, 27, was tortured and forced to falsely confess to being a CIA agent before the Cambodians killed him.
He spent several years in Darwin before buying a yacht and being captured in Cambodian waters in August 1978.
Rob Hamill testified at the Khmer Rouge Tribunal in the case against the party's torture master Guek Eav Kaing -- known as Comrade Duch -- in Phnom Penh last year.
The verdict is set to be handed down on July 26, and Mr Hamill, 46, plans to attend the sentencing.
The New Zealander is now asking people who met his brother in Darwin to shed some light on his life there, the Northern Territory News reported. He said any information, photographs - or even video footage - was "precious" and would help the family come to terms with the tragic loss.
"Just anything would help," he said.
Kerry Hamill arrived in Darwin as part of an overseas adventure, after Cyclone Tracy hit on Christmas Eve in 1974.
He worked with Riteway Concrete, helping build Anula school, before moving in with Canadian Stuart Glass and his wife Susan. The two men bought a yacht, Foxy Lady and together with Englishman John Dewhurst sailed to southeast Asia until their boat was blown into Cambodian waters.
Mr Glass was killed as soon as the crew were captured by the Khmer Rouge.
The other two members were held at the S21 prison - a former high school which was turned into a torture facility - until they died.
The Hamill family only found out about the capture 16 months later, in a story in their local newspaper.
The Khmer Rouge killed and tortured thousands of people while they governed the country from 1975 to 1979.
Duch, who as a young student won national mathematics prizes, designed the torture factory, in which 20,000 people are believed to have died.
Mr Hamill has formally requested an interview with Duch and expects to find out after the sentencing whether the request has been approved.
"I want as much information about my brother as I can get. And I really want to understand him (Duch)," Mr Hamill said.
He believed Duch should be sentenced to 40 years - "the rest of his living days" - the term sought by the prosecution.
"Anything less than that would be a victory to the (Duch) defence team, I suspect. He took my brother's freedom away, he took away 14,000 others' freedom . . . he should really have his freedom taken away too".
Mr Hamill said he would also visit sites in northern Cambodia to film a documentary, Brother Number One.