Originally Posted by Drunken.Broncoholic
When you're staring down a life sentence in a prison the rest of your life suicide becomes an option. When its a murder suicide most of the time the person kills themselves not because of the troubles of life, but rather they don't want to spend life in prison.
Murder-suicides also happen in countries where you would not get life for a single murder, which disproves your theory.
Most murder suicides happen as crimes of desperation, typically one party is threatening to leave and/or take the kids and the other will in desperation commit murder to prevent it - once the remorse sets in, suicide becomes the only response to atone for murdering a loved one.