Is what happened during the era of Umar ibn al-Khattab, concerning the story of the young man who killed the father of three individuals, and whom Abu Dharr vouched for, and then the children of the slain man forgave him; historically accurate?

Reading the story obviates the need to research its authenticity, as it contains oddities that are unfitting for the jurisprudence of the Companions. No chain of transmission (sanad) has been found for it, and it has only been mentioned in books of قصص (stories) and نوادر (anecdotes), such as "Nawadir al-Khulafa'" by al-Itlidi, and "Majani al-Adab" by Louis Cheikho.