What snaps that causes someone to kill his or her family?

SALEM, Ore. – The headlines this week are enough to make your stomach church. In two different cases, police said fathers are suspected of murdering members of their families before ending their own lives.

On Monday investigators said Steven Givens stabbed himself to death shortly after his wife was stabbed to death in their house. In that case, it appears Steven killed his wife.

Then on Tuesday police in Salem said a mother and her three young children were murdered in their home before it was set on fire. The father in the family was later found dead in a car 80 miles away.

These cases and others like it during the past year raise an uncomfortable question – what kind of person is capable of killing members of their own family?

When we started digging through our news archives we were startled at just how many similar cases popped up.

In one 2009 script we saw references to six murder/suicides in just one month. Those crimes claimed the lives of 15 people.

In many cases, neighbors told us they didn’t see any warning signs.

Take the case of Tuan Dao. In 2011, Dao blew up his Vancouver home killing himself and his five children.

Later court video surfaced of Dao when he was accused of attacking his wife. The estranged couple also faced bankruptcy.

Financial strain and the embarrassment of a divorce are common factors for what’s called “familicide,” according to psychologist Frank Colistro.

“They tend to be what we call ‘resentment hoarders,’” Colistro explained. “Every time they think about whatever it is they’re resentful over, the anger produces that much more pressure to act.”

Colistro said there’s no single profile of someone who kills his or her family. He said some are psychopaths, such as Christian Longo, who Colistro thinks simply wanted to be single again.

In the Salem case with the Lazukin family, we simply don’t know what kind of stresses the husband might have been facing.

The family’s landlord tells us that the rent was always paid on time, even early, and the family improved the property with new paint and landscaping.

Whatever his issue, Colistro said the father likely stewed over it for a long time.

“The fantasy goes, one way out of this is to kind of give the world a great big ‘F you,’” Colistro said. “(They think) here it goes out to all my debtors, all the people giving me a hard time. I’m going to erase the family and then I’m going to erase myself.”

Colistro said the more a person fantasizes about killing, the easier it becomes to actually do it.