This is a nice story which I read in the Quran interpretation of the aya in the Quran 17: 33
concerning this subject:
Some policemen went from Baghdad [in the middle of Iraq] to Mosul [in the north of Iraq] taking with them some detained men, to hand them over to the Mosul police.
After they accomplished their duty, and intended to return to Baghdad, they saw a man in the railway station, intending also to go to Baghdad, but his money were not sufficient to buy the ticket for the journey by the train;
so they said to him: “Come with us by the train, and we put the handcuffs on your hands, then when the collector comes, we will say to him: This is a detained man sent by the court to Baghdad, so he will leave you and go his way. Then we shall unlock the handcuffs from your hands after he leaves us.”
The man agreed about that, and they put the handcuffs on his hands and locked it. Then the train moved and their plan succeeded.
Later on, the policeman, who carried the key, protruded his head out of the train window to see something in the desert, while the train was quickly moving, and the key fell from his hand in the desert, so the hands of the man remained bound with the locked handcuffs. They tried to unlock it without the key, but could not succeed, so the police said to him: “When we shall arrive at Baghdad, we shall go to a blacksmith to unlock the handcuffs for you.”
Then when they arrived at Baghdad, they took him to a blacksmith, and said to him: “Unlock the handcuffs for this man.”
But when the blacksmith saw him, he recognized and seized him, and said to the police: “This man killed my father and escaped few years ago, and I futilely searched about him but could not find him; and he has now come to me upon his feet. Now, take us to the police officer and don’t unlock his handcuffs.”
So they took them both to the police detective, and the blacksmith proved his claim about the man in the court and retaliated of him.
Therefore, this incident confirms His saying – be glorified – in this aya, which means:
Whoso is slain wrongfully [and undeservedly], We have given to his heir power [on the murderer by means of retaliation]