A son testifying against his father in a murder case

Q 1: A young man saw his father killing another person unjustly. The father imposed on the son keeping this secret threatening him that he would be angry with him the rest of his life if he revealed it. Afterwards, the police arrested an innocent person for this crime. The young man has managed to keep this secret for a while, but he does not know what to do anymore. Should he testify the truth and become undutiful in his father, keep this secret and become silent, or should he apply Allah's Shari`ah (Islamic law) mentioned in the noble Ayahs (Qur'anic verses): In the name of Allah, the Most Gracious, the Most Merciful But if they (both) strive against you to make you join in worship with Me others that of which you have no knowledge, then obey them not; but behave with them in the world kindly What should he do in both matters? (Part No. 25; Page No. 271

A: You must declare the truth about what your father did and should not conceal it, for Allah (Glorified and Exalted be He) states: O you who believe! Stand out firmly for justice, as witnesses to Allâh, even though it be against yourselves, or your parents, or your kin This is not considered undutifulness to your father, because Allah has commanded this, and there is no obedience to a creature when it involves disobedience to the Creator.