Consequences of sin

One young person was always aggressive and violent. In the local town he was feared by common people. On one occasion, he murdered a businessman on the main market street. He threated that no one should give witness against him. Police arrested him and was in jail. The police were not able to file a charge sheet as they did not have any witness.
Meanwhile, this young man heard the gospel shared by one fellow-prisoner who was arrested for preaching the gospel. The murdered was convicted, repented, asked forgiveness from the Lord, and was transformed. After few weeks, he was given a ‘parole’ for a week. He went home and visited the church, his friend in jail recommended. Some of his old friends suggested that he should not ‘confess’ his crime instead deny. As there are no witnesses, he would be set free. On Sunday, in the church, he made a commitment that he would ‘confess’ his crime and accept the consequences and will not tell lie. “Whoever conceals his transgressions will not prosper, but he who confesses and forsakes them will obtain mercy.” (Proverbs 28:13)
On Monday, he went to the jail authorities to surrender as his leave was over. Jailor searched for his file but could not find. For whole day few jail staff searched nook and corner for his file. None was found. Jailor said to the young man, go home, if we find the file, we will call you back. The call did not come for nearly two decades, this murderer-prisoner has become a pastor of a growing dynamic church.
God forgives our sins. However, there is no guarantee that a person could escape the consequences of sin. Nevertheless, God could be gracious to even wipe the consequences.
Do I confess my sins or try to conceal it?