I know this is hard to fathom for a lot of folks, but just Google it and you'll be shocked at how common it actually is. Thousands of cases; many of which don't receive national media exposure:
"One motive behind some cases of filicide -- the act of a parent killing a child -- is spousal revenge.
People motivated by spousal revenge want to take away the thing that is most precious to the spouse. The children are used as "an object in this war that they see with this other person," said Dr. Susan Hatters-Friedman, an associate professor of psychiatry and pediatrics at Case Western Reserve University School of Medicine in Cleveland.
"It would be counterintuitive to the vast majority of the population that if you're mad at your ex-wife, you would kill your kids to get back at her," Hatters-Friedman said. "In order for those thoughts to cross (their) mind, often it would be someone with a personality disorder."
Dr. David Adams, a Boston psychologist who directs a national project to train police and prosecutors on assessing domestic violence dangers, said narcissistic personality disorder is common in men who commit filicide motivated by spousal revenge.
Those with the disorder can be grandiose in their thinking, have a limited capacity for empathy,
see themselves as victims, and take many things as signs of disloyalty, said Adams, who also founded Emerge, a Boston counseling center for men who abuse their partners.
"When they suffer what's called a narcissistic injury -- when their ego is wounded, so to speak -- then they strike out with narcissistic rage, like they want to destroy the person who hurt them," Adams said.
"Some fathers want to leave the mothers feeling guilt and remorse for the rest of their lives," he said.
more:
http://www.twincities.com/localnews/ci_21142127/river-falls-murder-hearing-today