A prominent North Korean defector who recanted parts of the dramatic tale of his escape from a prison camp may have changed his story after seeing a video message from his father, who he thought was dead.

Shin Dong-hyuk said he was tormented to see his father alive and speaking in the video released by Pyongyang in October.

On Sunday, Shin, one of the best known defectors from North Korea and a key witness to the UN inquiry, which has issued a damning indictment of the isolated country’s rights abuses, said in a post on his Facebook page that he had changed key parts of his story, and then apologised.

Shin gave no details. A statement from Blaine Harden, the author of a bestselling book on Shin, said much of the revised account was consistent with the original version and with his testimony to the UN commission. “But he has significantly revised details of his early life and substantially changed the dates and places of major events,” Harden said.

Michael Kirby, an Australian judge who headed the UN commission of inquiry, said the trigger might have been the North Korean propaganda video of his father. “His father said various things about his testimony,” Kirby told Reuters.

In the video, his father told Shin to “come to your senses and return to the embrace of the party”, referring to the ruling Workers’ party. He also referred to discrepancies in Shin’s story. It was not clear why the video would have compelled Shin to change his account but after his father’s comments other defectors have raised questions about what appeared to be discrepancies.

Shin said in October the video may have been a veiled threat that his father would be killed if he did not keep quiet. But he was reluctant to discuss the inconsistencies that his father referred to. Kirby said the changes in Shin’s account did not affect his commission’s report on human rights abuses in North Korea.

“It’s part of the testimony of one witness whose testimony is referred to on one page of a 350-page report that includes the testimony of hundreds of other people, so keep it in proportion,” said Kirby. On Shin, he said: “He’s not a fraud. He bears wounds that can be identified and are corroborative of his story of torture by flame and by beating.

“It appears to be related to whether he was in one detention camp or in another. It’s a question of whether he was in the most gruesome or simply one that is very gruesome.“

In the video, Shin’s father speaks about the family living in an area that was once the site of one of North Korea’s prisons, Camp 18. That seems to contradict Shin’s initial story about being born and living all his life in Camp 14, a facility known for harsher human rights abuses.

Harden, who wrote the book Escape From Camp 14, said Shin has now revealed he twice escaped from Camp 18 when he was a teenager, first in 1999 and then in 2001. Shin now also says he was tortured when he was 20, as punishment for escaping, not 13 as in the story he has been telling for nine years.

“I didn’t realise that changing these details would be important,” Harden quoted Shin as saying in the statement. He has not changed his account that he escaped from Camp 14 in 2005.

Kim Young-soon, a survivor of the notorious Yodok prison, Camp 15, said Shin had changed crucial elements of his story before. Many defectors embellished their stories, she said. “We shouldn’t blame defectors but we should be careful when we see some defectors talking incoherently, making things up and lying to make themselves more valuable,” Kim said in an interview.

“I am not saying that Shin was a bad guy. He suffered at a young age. But I hope in this defector community, there will be only honesty, without any lies to make money.”