Someone linked this article recently, but I've not had time to study it. When skimming, this jumped out at me:
The father is almost always considering suicide as the only escape from some sort of financial crisis. Murdering his family members, then, becomes a way of rescuing them from the hardship and shame of bankruptcy and suicide. "There is no other solution but the one you find today," wrote Russell Gilman, a Scottsdale attorney who
murdered his wife and two kids after the family finances fell apart, in a note he left behind. (Economic duress can also play a role in rage killings, though it's not usually the main trigger.)
Inside the Mind of Family Annihilators