Seems most likely he semi-accidentally killed her then did the right thing and killed himself. If he wrote about it that would be great so we can all have some closure. A hot girl can't just die like this without any legitimate explanation. She was blonde! and white hot! She did yoga for her anxiety! We need closure!
Remember the couple that found the van? Their channel spotlights a different missing person every week with paths for people to get in touch with the authorities/themselves if they have any info.