Son broke down when he told about the "ridiculous" match-fixing allegations on Wednesday, which he denies. He accuses China of threatening him to get him to confess to crimes he did not commit.
Earlier in the week, he was one of 43 people banned from football in China for life due to match-fixing.
Now, Son, who played four matches for South Korea in the 2022 World Championship, says Chinese police used threats against his wife and children to get him to confess.
It was ridiculous allegations. They threatened that my wife would also be accused if I didn't confess. And said "how will the children manage if your wife also comes here? So confess quickly", says Son.
He says he did not have access to an adequate translator or lawyer. And that he never got to know any details about what he was accused of.
The South Korean says tearfully to the journalists that he was offered a deal that if he confessed, he would be released quickly.
I was worried about my family and had no choice, but confessed to allegations I didn't even understand to get back home.
He wants the Chinese police to release videos from his interrogation to clear his name.
Son's agent Park Dae-Yeon says he doesn't believe the player risks sanctions from the International Football Federation (Fifa) since China couldn't prove that he did anything wrong.