Yoon Jong-soo, 79, died Monday after testing positive for the novel coronavirus Dec. 26, according to representatives of Abductees' Family Union in the South, Yonhap reported Tuesday.
Yoon was among a group of 33 South Korean fishermen who were on board the Cheongwangho, a fishing boat captured in the East Sea in August 1975.
In 2008, Yoon attempted to flee the North with his wife and daughter, but family members were detained while Yoon was able to escape to China and seek asylum at the South Korean consulate in Shenyang, according to reports.
Choi Sung-yong, head of Abductees' Family Union, said Tuesday that Yoon was distressed about family left behind in the North at the time of his death.
"The deceased tried to rescue his daughter who remained in North Korea," Choi said. "He was troubled from not knowing about her status."
Choi urged North Korean authorities to confirm the status of all South Korean abductees and their families in order to abide by the "moral laws of family relationships."
In North Korea Yoon met and married an ethnic Korean woman from Japan, activists said. Together, they had one child. Yoon worked at a North Korean plant producing agricultural machinery for close to 30 years, according to News 1.
Hundreds of South Koreans abducted to the North after the 1950-53 Korean War remain unaccounted for. According to South Korean newspaper Chosun Ilbo, Yoon was the fourth person to defect among the Cheonwangho crew, and only the eighth South Korean citizen to successfully escape the North.
Yoon's younger sister told the newspaper Tuesday that her brother avoided staging anti-North Korean protests in the South because he feared retaliation from Pyongyang. Yoon worried whether his daughter was sentenced to a political prison camp in North Korea, she said.
North Korea has claimed previously that no South Korean abduction victims were in the country and that former South Koreans remain in the country of their own free will.