GENEVA — A United Nations panel has served notice to Kim Jong-un, the North Korean leader, that he may be personally held liable in court for crimes against humanity committed by state institutions and officials under his direct control.

A letter conveying this notice is part of a report by the panel to the United Nations Human Rights Council, released Monday after a yearlong investigation.

The report is viewed by rights activists not only as the most detailed and authoritative body of data on the state of human rights in North Korea, but also as a milestone in the international debate on one of the world’s most reclusive and isolated countries.

In the letter, dated Jan. 20, the panel chairman, the retired Australian judge Michael Donald Kirby, summarized the investigation’s findings of crimes against humanity committed by officials that could be inferred to be acting under Mr. Kim’s personal control.