Phnom Penh, Cambodia (CNN) -- A man who ran a notorious torture prison where more than 14,000 people died during the Khmer Rouge regime was found guilty of war crimes Monday and sentenced to 35 years in prison -- with five years taken off that sentence for time served.

The verdict against Kaing Guek Eav, alias Duch, also convicted him of crimes against humanity, murder and torture. It was a historic first for a U.N.-backed war crimes tribunal.

Duch, 67, was the head of the S-21 prison, where at least 14,000 people died.

"It's clear that he will never be a free man again," said Youk Chhang, director of Documentation Center of Cambodia.

Prosecutors had asked for a 45-year sentence with five years' credit for time served.

Duch pleaded guilty but said he was only following orders and asked for forgiveness.

In the last week of the trial, he argued that international law did not apply to him because he was following orders.

Few people brought to the prison made it out alive; only about a dozen were found by the Vietnamese who invaded Cambodia in 1979.

Duch has acknowledged his role overseeing the prison but has sought release after 10 years in detention, angering survivors.

Outside the court on Monday, hundreds of Cambodians, including the Muslim minority known as Cham, watched previous court sessions on large television screens.

Timeline: Rise of Khmer Rouge and its aftermath

"We want to hear directly from the court what the verdict will be," said Tin Mosa, who along with 40 others from the Cham group, got up early Monday to come to the court.

"I can assume that the international court is good enough to bring justice for the Cambodian people, especially for me," he said. "I want to see Duch die in jail."

More than 10 million Cambodians were expected to watch the live broadcast of the verdict being televised across the country, said Reach Sambath, the spokesman for the court.

"Today is a historic important day for the people of Cambodia," Sambath said.

At least 1.7 million people -- nearly a quarter of Cambodia's population -- died under the 1975-1979 Khmer Rouge regime from execution, disease, starvation and overwork, according to the Documentation Center of Cambodia.

Another four of the ultra-Maoist regime's former leaders are waiting to see if they will stand trial before a U.N.-backed tribunal for war crimes and crimes against humanity.

The tribunal began its work in 2007 after a decade of on-and-off negotiations between the United Nations and Cambodia over the structure and the functioning of the court.

Chhang, director of the documentation center, said his organization was holding verdict watch gatherings in seven provinces so that rural Cambodians could observe.

Chhang said the verdict may not suit everyone, but he thinks Cambodians will be able to turn over a new leaf once the verdict is announced.

"This is what we have, and then we must move [on]. We have our own identity now, our own family, our own society now. We have to build it, make it strong, to prevent [the past] from happening" again," he said.

On Sunday, parents, siblings, friends and loved ones gathered before monks in a courtyard of the prison site -- now a museum -- to participate in a ceremony to honor the dead. Among them were survivors of S-21, such as Bou Meng, who wept at times during the memorial.

"I have been waiting for justice for 30 years," he said. "If the verdict does not please me, I will be disappointed forever."

Eng Chanthy, 47, lost her father, six brothers and grandfather to the Khmer Rouge due to starvation.

"I believe that justice will be brought by the tribunal court," Chanthy said."I heard Duch was apologizing to the Cambodian people and asking the people to pardon to him, and I don't agree with him asking for freedom."

"I feel that Duch should die in prison. I don't want to see him live in freedom," she said.