Chau Van Kham, who had been in jail for four years on national security charges, has returned home to Australia.

The retired baker was arrested on national security charges during a research trip to Vietnam in 2019, and accused of entering the country illegally from Cambodia. In November of that year, after a trial that lasted only five hours, he was found guilty and jailed for 12 years.

The family’s lawyer Dan Nguyen told Australia’s national broadcaster ABC that the family was relieved the 74-year-old was finally home.

“Twelve years is almost like a death sentence for somebody his age, but we’re so happy that he’s home, and we’re so happy that he’s home a free man,” she said.

Kham has been reunited with his wife and two children in Sydney.

In a statement, he thanked well-wishers and the Australian government for its support. Australian Prime Minister Anthony Albanese made representations on Kham’s behalf when he visited Vietnam in June.

“The family asks for privacy at this emotional time of reunion,” Nguyen added.

The Australian government thanked Vietnam for Kham’s release, saying it learned of the decision overnight.

“They have done this on the basis of humanitarian grounds and in the spirit of friendship which exists between Australia and Vietnam,” Deputy Prime Minister Richard Marles told reporters.

“This is a result of careful advocacy which has been undertaken by the Australian government with the Vietnamese government over a number of months now.”

Human Rights Watch welcomed Kham’s release as “fantastic news” noting that his trial had raised serious due process concerns.

“Chau Van Kham is just one of more than 150 political prisoners in Vietnam, held for peaceful acts of free expression,” Elaine Pearson, Asia director at Human Rights Watch, said in a statement. “The one-party state has no tolerance for anyone who expresses a narrative contrary to the government.”

Amnesty International said the activist’s release was a “momentous day”.

Kham’s case was based on his links and activities with the opposition group Viet Tan, which Hanoi designated a “terrorist organisation” in 2016.

Viet Tan, which operates lawfully in countries including Australia, denies the claim and says it “advocates for social justice and democratic change through peaceful means”.

Kham is a former sailor who fought on the side of the South during the Vietnam War, fleeing on a boat in 1983 after the fall of Saigon – now called Ho Chi Minh City – and eventually settling in Australia