'Alaqama bin Wa'il reported on the authority of his father that a person was brought to the Messenger of Allah (ﷺ) who had killed another person, and the heir of the person slain had dragged him (to the Holy Prophet) with a strap around his neck. As he turned away Allah's Messenger (ﷺ) said: The killer and the killed are (doomed) to fire. A person came to the other person (the heir of the deceased) and he reported to him the words of the Messenger of Allah (ﷺ) , and so he let him off. Isma'il bin Salim said: I made a mention of it to Habib bin Abu Thabit and he said: Ibn Ashwa' reported to me that Allah's Apostle (ﷺ) had asked him to pardon him, but he refused.
Hadith Referenceصحيح مسلم / كتاب القسامة والمحاربين والقصاص والديات / 1680