When Does Religion Go Horribly Wrong?

This is perhaps one of the most tragic episodes in American history where John List, a devout Christian, violently murdered his family; wife, three children and his mother.

He fled his home where he left his family's bodies a note stating that he saw too much evil in the world, and he had killed his family to save their souls. He later argued that the letter he left behind at the crime scene, essentially his confession, was a confidential communication to his pastor and therefore inadmissible as evidence at his trial.
When asked why he had not taken his own life, he said he believed that suicide would have barred him from Heaven, where he hoped to be reunited with his family.
https://en.wikipedia.org...

List was a man obsessed by his religion and lived his life to the letter of the Bible, also enforcing it on his family. Everything about the whole grizzly episode was religiously inspired, so is there every reason to assume that, had it not been for this man's religion, there would have been a completely different outcome?