An article titled "A Guide to the Perplexed about the Permissibility of Killing Prisoners" says Islamic scholars present five approaches drawn from various interpretations of the Quran:
A polytheist prisoner must be killed. No amnesty may be granted to him, nor can he be ransomed.
All infidel polytheists and the People of the Book (i.e., Jews and Christians) are to be killed. They may not be granted amnesty, nor can they be ransomed.
Amnesty and ransom are the only two ways to deal with (surviving) prisoners.
Amnesty and ransom are possible only after the killing of a large number of prisoners.
The Imam, or someone acting on his behalf, can choose between killing, amnesty, ransom or enslaving the prisoner.
The author indicates the last option as his preference, explaining that Islam's prophet, Muhammad, had dealt with prisoners in different ways to maximize the benefits to Muslims. He gives examples of methods with which Muhammad had chosen to kill, grant amnesty and ransom prisoners.
The article was a reaction, the author said, to criticism by Muslims that had "torn his heart," concerning the execution of nine Russian prisoners after the government had refused to surrender "one of Russia's biggest criminals and crooks."
According to the author, the Chechens have executed prisoners not because of their heart's desire, but because they have seen a benefit for the Muslims in such an act.
Some critics have argued, the author notes, that no one should be punished for the sins of others. He insists, however, that Allah permits the killing of a prisoner because he is a prisoner and all the more so if one's killing for the sins of others serves an important Islamic interest, as well as a deterrent to the enemy.