Trying to explain the unexplainable: In 4 days, 4 mass killings of 4 families in 4 states

America witnessed a chilling series of horrors over four bloody days in the past week — four mass killings involving four different families in four states. Criminologists say this tragic cluster of deaths is random. Yet domestic violence researcher Tricia Bent-Goodley notes that people still feel a need to make sense out of crimes that are this horrible.

Bent-Goodley says that each week, nine women are killed by an intimate partner. So she says these four killings are a reminder that home is not a safe place for everyone.

The killings began Saturday, and left 14 adults and seven children dead.

University of Texas professor Alejandro del Carmen says it might seem as if deadly violence has increased because the Internet spreads vivid news globally in almost real time.