"I don't understand what the word 'genocide' means," he says. "I don't want to talk about the past. I want people to forget my past. I can't explain what happened."
Ta An is one of the four most wanted people in Cambodia, according to the UN tribunal set up in 2006 to try those responsible for the death of 2.2 million people during Pol Pot's twisted attempt to remake Cambodia into an agrarian paradise of equality. Pol Pot died in 1997, aged 72, while under house arrest by a rival Khmer Rouge faction.
Prosecutors believe the fanatical Ta An oversaw the killing of 150,000 people. They have recommended that he and three other surviving Khmer Rouge commanders be charged with genocide, crimes against humanity, murder, torture, rape and religious persecution.
"The jurisdiction of the tribunal is such that the senior leaders and those most responsible can be put on trial," said William Smith, an Australian prosecutor in the Cambodian capital, Phnom Penh. "We believe these four people meet those criteria."
But seven years after the tribunal charged the first five members of the Khmer Rouge leadership, only one has been convicted: Duch, who ran Phnom Penh's infamous S-21 concentration camp where about 17,000 people were tortured before being killed, was sentenced to 35 years in jail in 2010 for his crimes against humanity.
Of the others, one has died, the prosecution of another was abandoned on medical grounds and two are still in the process of being tried.
Now, Cambodia is increasingly divided over whether Ta An and three fellow suspects should be put on trial at all. And with the country preparing for national elections next weekend, it has become a partisan debate in which even the victims of the Khmer Rouge are divided.
Chum Mey, 83, is one of just three people alive who survived being incarcerated in S-21. He is now disillusioned with the tribunal's snail-like pace and the £100 million ($192 million) spent so far on trials.
"I feel very disappointed that the tribunal has taken so many years and only Duch has been convicted," said Chum. "If I'd known how much the tribunal would cost, I would have said the money should be spent on developing the country instead."
He doesn't think there should be more trials, despite having seen his wife shot by the Khmer Rouge.
"Once the current cases are finished, the court should stop," he said. "I blame the top leadership, the ones already charged. They were all educated men, yet still they did such bad things.
"Men like Ta An were also evil, but not as bad. They were just following Pol Pot's orders."
Chum is a supporter of the country's Prime Minister, Hun Sen, and his ruling Cambodian People's Party (CPP). Hun is an ex-Khmer Rouge commander who has held on to power for 28 years by manipulating electoral rolls and intimidating and imprisoning opponents.
He wants the UN tribunal to leave, and insists there will be no more prosecutions.
Victims who are not allied with the CPP are less forgiving.
"I want the cases against Ta An and the others to go ahead," said Bou Meng, 72, an artist whose wife was tortured and killed in S-21. "They should be tried for their crimes. If the tribunal won't do it, then the cases should go to the international court in The Hague. Maybe they can give justice to Cambodia."
The decision on whether to charge the four further suspects is not expected until the end of the year.
