Karzai impunity

The Karzai government passed a law that gives amnesty to perpetrators of atrocities.
The National Stability and Reconciliation Law was passed by parliament in 2007 by a coalition of powerful warlords and their supporters to prevent the prosecution of individuals responsible for large-scale human rights abuses in the preceding decades. The amnesty law states that all those who were engaged in armed conflict before the formation of the Interim Administration in Afghanistan in December 2001 shall "enjoy all their legal rights and shall not be prosecuted."
After the amnesty law was passed by parliament in 2007, President Karzai said he would not sign it. The chairperson of the AIHRC, Dr. Sima Samar, told Human Rights Watch that she had been offered assurances that he would not enact the law: "The president himself promised me twice that he would not sign the law." Despite this commitment, and similar promises to a range of civil society groups, the law was published in the official gazette. It is not clear when this happened, as the date on the gazetted law is December 2008, while some sources say it was not published until January 2010, when printed copies of the law were received by organizations that monitor the gazette.

Importantly:
The law says that those engaged in current hostilities will be granted immunity if they agree to reconciliation with the government, effectively providing amnesty for future crimes.
"The amnesty law is an invitation for future human rights abuses," said Adams. "It allows insurgent commanders to get away with mass murder. All they need to do is offer to join the government and renounce violence and all past crimes will be forgiven - including crimes against humanity."
Defenders of the amnesty law say that it still allows individuals to bring criminal claims against perpetrators. However, international law requires states to investigate and prosecute crimes against humanity, war crimes and other serious human rights violations, such as extrajudicial killings, torture and enforced disappearances. Such obligations cannot be transferred to individuals.

Also:
The law also says that Taliban who have killed and committed abuses but who lay down their weapons will not be prosecuted--an attempt to encourage reconciliation. This is also impunity.