OSAKA -- A Japan-based citizens' group that aids North Koreans is demanding a full police investigation into the slaying of a 51-year-old Korean activist for human rights in North Korea at his home in Hyogo Prefecture, the group said Sunday.

Rescue the North Korean People! Urgent Action Network (RENK) suggested Sunday that North Korean agents may have been involved in the fatal stabbing last month of Kim Yong Dal, a RENK representative.

Kim, also a lecturer at Kansai University's Institute of Human Rights Studies, was found dead with stab wounds to his chest May 8 by the owner of his apartment in the city of Amagasaki, police said. The Aichi Prefecture native was killed around April 26 to 28, they said.