I'd like to say something about the concept of justice in general.
The biblical line we have in the current bible is 'An eye for an eye, and a tooth for a tooth'.
In the Qur'an it says 'An eye for an eye, and a tooth for a tooth, and the instigator is the guilty party.'
There is an important qualifier in that last condition. It speaks of the relationship between the victim and the offender. The offender is to be punished by the victim in a way that is proportionate to the offense. The victim is the one who has the personal right to retribution. As the instigator is the guilty party, and not the retaliator, the offender cannot seek retribution from the victim after they have taken the punishment, as retaliation is not instigation, and so there is no guilt placed on the victim. This means that by that law, there cannot be back and forth revenge attacks.
That's not to say that back and forth retribution won't occur. Only that it is not Just according to the law.
Some people say that to return in kind makes you just as 'bad' as the original offender, as you are doing the same thing. For example, if a person breaks my arm and I respond by breaking that person's arm, then I would be labeled as being just as guilty with this line of thinking, on the basis that I have committed the same foul act. This is saying something illogical. The error here is in equating instigation with retaliation. In this example, if I had not first had my arm broken, then I would not have broken the offenders arm in turn. And so the first act is one of instigation, while the second act is one of retaliation, meaning that they are not equal, and so no guilt can be placed on the victim. If you were to have a short and general definition of injustice, it would be something along the lines of 'To treat equally that which is not equal.'
The victim is the one who has the personal right to retribution. Meaning, that if someone breaks my arm, unrelated Jason from the neighbouring suburb does not have the right to break the arm of the offender. In general, no unrelated person has the right to enact the punishment. In the case of murder, the next of kin has the right to take the life of the offender, without due cause for counter-retribution by the next of kin of the original offender.
I have heard some people misinterpret the 'eye for an eye' analogy in this case, by saying: 'You killed my brother, and so I kill your brother.' This is obviously wrong, as the punishment targets the offender for reasons of the offense.
The bible also says 'Let he who is without sin cast the first stone.'
Taken in context, what this means is that no imperfect human being has the right to administer biblical justice in any case that does not personally pertain to them. It does not mean that a person is disallowed from taking their rights.
The biggest problem with a person enacting their retributive rights is the justification process. A person must justify the guilt of the alleged offender to themselves without a shadow of a doubt through evidence and eye-witness accounting. Often times people will act on mere suspicions and heresay. If the person cannot soundly make this justification, then retribution is unjust, even if the alleged offender is actually guilty.
Normally this type of investigating requires a combination of highly skilled and expertly equipped people. But even these people and this equipment make plenty of mistakes. Only an omniscient being could possibly always be completely accurate in all judgements and know the exact details of all events ever, as well as all intentions behind all actions.
The point of all this is that the courts cannot administer justice because the entire process of investigating and judging is subject to errors at every step of the way. So, there should be no judicial body called the 'Justice System'. Also, individuals cannot always take their retribution in a Just manner, as they cannot always justify their judgement, even though they are directly involved and as such would be privvy and closer to the events.
Neither can the courts allow personal retribution, as to enforce it and prevent unjust counter-retribution, the courts would first have to justify the original retribution, which they cannot actually do.
I didn't even get into how a person is supposed to accurately calculate the exact and Just punishment for every case. As actions are measured by intention, it basically means that one would have to be a mind reader in order to know what is truly deserved.
Government, police and courts are necessary to keep civilization civil, but they are not nearly about being Just. 'The Justice System' should be renamed to something like 'The Civil Order System'. Don't look to justice from human people, as even the ones who would whole-heartedly adhere to it are not always able to know it and enact it.
So, if you believe in God, and you believe that God is Just, then you must be of the belief that everyone always gets exactly what they deserve, as otherwise God would not be Just. This should be quite a comfort in the face of so many unjust actions by people in the world.
Otherwise, we will never be a Just people as human beings, as long as we ever occupy this world.