I don't think she killed Travis in atonement for his sins, or that his killing had any symbolic relationship to Mormonism. She hadn't been a member of the church very long, she joined almost immediately after meeting Travis, and she never took the religion seriously, imo.
She couldn't have him, he rejected her so he had to die.
IMO
The reason I felt the temple ritual killing pantomimes might be a factor was because in her testimony she used the phrase "deep" faith or knowledge which is not given to new members, but is information that they learn later. Why would he be telling her this without telling her what they were?
Also, remember that she sent warnings to other women using religious lingo like "do not lie with Travis..." She also claimed they had many discussions involving religion. I don't for a minute believe she is a true believer in Mormonism, rather she used the knowledge to taunt Travis once he told her he was through with her.
Especially if he told her he was going to go to the bishop.
If Travis had told her what was taught in the temple, he would have to have the "penalty" for revealing that information or he could not go to the Celestial Kingdom. She would say, for example, "You know you have to shed your own blood for what you've done, don't you? I'm actually helping you repent!"
Somebody asked for a link - I posted a Christian one with more information on the thread "sequence of events." Many of you may already be familiar with the Lafferty case where a young mother and her eighteen month old daughter had their throats slit. The motive for the murder was entirely different, but the means of death strictly followed the temple instructions.
The murderer does this so that he/she may have "clean hands" in that they helped a guilty person atone with their own blood.
Here is a link to the photos in sequence. Look at the one where his head is down and he is standing -- I believe you can see blood on the shower wall. I also noticed blood pooling in the reddish area where he is reclining in the shower just before the camera falls. This is the first photo where the door is open. This is when he may have said he couldn't feel his legs because he may have been in shock or suffering from blood loss at that point. He may then have lunged at her, coming in low like she said, screaming and saying he would kill her.
She would have been jacked up on adrenaline and been extremely savage in her attack, some of the head wounds breaking bone. The wounds on his back are all at the correct angle for this position, him having his head in her stomach and pushing her back, down the hall and this is where her palm print appears on the wall. It also explains the bloody brush marks on the wall.
She shoves him off, stabs him again in the chest and tries to disembowel him. He curls up and tries to crawl away making horrible cries of agony. She's afraid someone will hear so she straddles him and cuts his throat using far too much force. She drags him back to the bathroom and--unbelievably--as she struggles to get him into the shower, he is still making noises and...looking at her. Now her adrenaline is going down and he is creeping her out. The pleasure is gone. SHe has to move him and the horrible sounds of death and those eyes are too much--she goes and gets the gun, wraps the pillow around it to muffle the noise and shoots him from a standing position, his head propped on the edge of the shower, angle correct.
I have to add that it was days before I could view the photos in this case without becoming lightheaded. My heart goes out to Travis' family whose lives she has also taken.
Thanks for all you do here to solve crimes, find the missing, and support victims.