Alston's reports to the UN relating to extrajudicial executions also dealt with broad thematic issues that arose in many countries, such as witchcraft and vigilante killings, national-level commissions of inquiry dealing with unlawful killings, the problem of prisoners running prisons, the importance of witness protection programs, the problem of governmental reprisals against individuals or groups who have cooperated with a UN human rights inquiry, the need to regulate the use of lethal force by law enforcement officers, shoot-to-kill policies, the relationship between human rights law and international humanitarian law, mercy killings in times of armed conflict, and the need to make military justice systems compatible with human rights. With respect to the death penalty, Alston's reports discussed the need for transparency, the unacceptability of the mandatory death penalty under international law, the definition of the 'most serious crimes' for which the death penalty may be imposed, the right to seek pardon or commutation of a death sentence, and the juvenile death penalty.