The Bible implores us to return to God and “hold fast to love and justice” (Hos 12:6). We should hunger and thirst for justice, but always with mercy as our utmost desire (Mt 5:6-7). Justice alone cannot change the world: only love can. Jesus revoked the Old Testament “eye for eye” (Deut 19:21), and warned us not to repay evil for evil (Mt 5:38-44). That shows the intimate link between charity and justice. Our judicial systems are as imperfect as the humans who operate them, so that unfortunately justice is not always served.
It is a Christian duty to strive for justice to prevail, especially for poor and marginalised people. If we suffer injustice, we can look at Jesus, the only truly just man, who also suffered unjustly. Reporting a crime to a reasonably trustworthy juridical system is no betrayal but a service to humanity. The Bible tells us to first quietly speak to a brother or sister who wrongs us, and when they do not listen to report them to the leaders of the community (Mt 18:15-17).