PHNOM PENH (AFP) - As the Khmer Rouge's head of state, Khieu Samphan was one of the few public faces of the brutal Cambodian regime.
The 83-year-old insisted he was not part of the Khmer Rouge killing machine - but could end his days in prison after he was jailed for life for crimes against humanity.
Throughout his historic trial, the French-educated radical denied he played a prominent role in a regime which oversaw the deaths of up to two million people in the late 1970s, saying he was kept out of leader Pol Pot's inner circle.
But Khieu Samphan was jailed for life on Thursday alongside "Brother Number Two" Nuon Chea, 88, by Cambodia's UN-backed war crimes court.
Lawyers for the pair - the most senior surviving ex-Khmer Rouge officials - say they will appeal.
During the trial Khieu Samphan had accused the prosecution of telling "fairytales".
"The reality was that I did not have any power and I did not care about it either," he said.
But he and Nuon Chea were accused by prosecutors of "spilling blood for power".
Like most Khmer Rouge leaders at the height of the regime's power, Khieu Samphan was a shadowy figure, his identity cloaked by the secrecy of the movement's inner circles.
But as the Khmer Rouge struggled for power in the civil war that followed their overthrow in 1979, he became the public face of the movement as it sought, and was to some extent granted, international credibility.
In the 1980s he held positions as prime minister of the communist government-in-exile and president of the party.
He was promoted by the Association of Southeast Asian Nations (ASEAN) regional bloc and other countries as a moderate voice of the regime.
A key player in peace talks in the early 1990s, Khieu Samphan remained the Khmer Rouge's most visible public figure until defecting from the then-dying movement in 1998 with Nuon Chea.
- Highly educated -
Born in 1931 in Cambodia's southeastern Svay Rieng province, Khieu Samphan was highly educated, graduating from high school and university in France.
The title of his doctoral dissertation, "Cambodia's economy and industrial development", offered a hint of the radical agrarian revolution that was to come.
He returned to join Cambodia's economic and social renaissance of the 1960s as an academic and journalist.
In the confused politics of the time, he was both condemned and elevated by the country's mercurial leader, then-prince Norodom Sihanouk.
As editor of a leftist newspaper at odds with the government, Khieu Samphan was beaten in the streets of the capital Phnom Penh and imprisoned in 1960 after Sihanouk branded him an "oppositionist".
But he was later elected to parliament and served as Sihanouk's commerce minister in 1962-63.
He fled to the jungle in 1967 after again becoming a target for his left-leaning politics, joining up with Pol Pot.
The Khmer Rouge eventually seized the country in 1975 and during the regime years Khieu Samphan was appointed head of state as well as to more powerful positions within the party and government.
It was in these roles that genocide researchers say he would have surely been aware of what was happening as one of the worst atrocities of the 20th century unfolded.
Evidence indicates he "personally contributed to those crimes by making public statements supporting the underlying policies", researchers Stephen Heder and Brian Tittemore write in their book "Seven Candidates for Prosecution".
"He publicly endorsed taking measures against the enemies of the revolution in a way that suggests knowledge and support of the policy of executing purported enemy agents." He was arrested in November 2007 on charges of war crimes, genocide and crimes against humanity.
During his trial, Khieu Samphan expressed a "sincere apology" but said that he was not aware at the time of the "great suffering" of the Cambodian people.
"I was not aware of the heinous acts committed by other leaders that caused tragedy for the nation and people," he said.
He showed no emotion in the dock as he was sentenced to life in jail.