God's forgiveness is not an automatic doorprize when one dies. The Bible is clear that repentance is the key to receiving forgiveness from God and avoiding eternal damnation. Those who sincerely repent and ask God for forgiveness (being sorry he got caught is not the same thing) are the ones who get forgiven.
God knows all the circumstances of our lives, down to every hair on our heads. UK's working-class youth are raised in an environment that openly mocks God, trashes any trace of pride in their heritage, advertises immorality and pushes drugs on them through sociolegal corruption. If this stupid clod commited this drastic crime while on drugs—and most probably against a background of negligence, poverty and ignorance by his and the birthmother's parents—God will take all of it into account.
In prison, he may have been forced into sobriety from drugs and alcohol for the first time in his life since childhood (or even before, if his mother drank or drugged during pregnancy), during which time he may have been able to see his horrible sin clearly, because God gives each of us an inborn conscience. We don't know if this miserable sinner repented after his arrest and conviction and before his death; but God knows.
We’re taught that if we repent and ask for forgiveness we will be forgiven. So someone who rapes a child, sincerely repents and asks for forgiveness, will be forgiven. That’s God’s call and I accept it. My problem is I have to forgive the evil creep, too, or I won’t be forgiven. I just hope when I get to heaven I won’t know everyone else’s sin.