The U.N. Human Rights Office says it’s “deeply concerned” by the pardons.

“These four individuals were given sentences ranging from 12 years to life imprisonment, including on charges of first-degree murder,” spokesperson Marta Hurtado said in a statement. “Pardoning them contributes to impunity and has the effect of emboldening others to commit such crimes in the future.”

“By investigating these crimes and completing legal proceedings, the US complied with its obligations under international law,” she added. “Victims of gross human rights violations and serious violations of international humanitarian law also have the right to a remedy. This includes the right to see perpetrators serve punishments proportionate to the seriousness of their conduct.”

Human Rights Watch says the pardons “show contempt for the rule of law.”