Shigeru Yokota, whose daughter Megumi was abducted to North Korea in 1977 and who played a central role in Japan's efforts to pressure Pyongyang to release more victims, has died, sources close to his family said Friday. He was 87.

Yokota, who worked with other victims' relatives to prod the government into rescuing their children and siblings, whom they believe are still alive, died without ever seeing Megumi again. She was kidnapped on her way home from school at the age of 13.

At the time, the family was living in Niigata Prefecture after Yokota, then employed by the Bank of Japan, was transferred to a branch of the central bank on the Sea of Japan coast.