Ezekiel 18:23 NASB
Do I have any pleasure in the death of the wicked,” declares the Lord GOD, “ rather than that he should turn from his ways and live?
Ezekiel 33:11 NASB
Say to them, ‘ As I live!’ declares the Lord GOD, ‘I take no pleasure in the death of the wicked, but rather that the wicked turn from his way and live. Turn back, turn back from your evil ways! Why then will you die, O house of Israel?’
I'm not sure the question is the correct one to ask here. God sees our situation differently from our views. We can only see the here and now, located right here in our own little corners of the world. We see things in the finite realm. We are born with an innate sense of justice, which such an horrific crime greatly offends. God, however, sees the whole picture in eternity. God is so much bigger than our existence and awareness. While He takes no pleasure in the sin of a human being raping another human being, His perspective of the crime is not the same as ours.
I believe in the death penalty, but I understand that the Biblical purpose of that penalty was more to remove a great sin from the Israelite society rather than anything punitive to the criminal. God is absolutely just in His judgments. He is also absolutely merciful in His mercy. He cannot make mistakes or do anything wrong. We can't even come close to that standard.