If someone who has commited a sin ..confesses to their priest/bishop and are felt to be truely contrite and are prepared to do appropriate pennance, then that sin should be forgiven by the church ...... thats how I understand it.
Am I wrong???
By the way I'm not a Catholic or even a regular church goer
But if forgiveness of sin/absolution is something you believe in then you have to apply it to all sins even ciminal activity.