What is the ruling on swearing a false oath before a judge to exonerate a culprit?

Lying without an oath is unlawful except in cases of necessity, and the prohibition becomes more severe if the oath is sworn upon a lie, which is the "al-Yameen al-Ghamus" (the diving oath) that is considered one of the major sins. One who swears falsely must offer sincere repentance, and the majority of scholars do not consider expiation necessary for it. Bearing false witness is also forbidden and is one of the greatest major sins. If the forgery of the cousin (son of the maternal aunt) is proven, it is not permissible to strive for his acquittal or to swear an oath regarding his innocence. However, if he is innocent, lying is permissible for a preponderant benefit or to ward off harm from a Muslim. It is preferable to use circumlocution (tawriya) to avoid lying.