And over the past year it's happened a number of times in Arkansas, including just this week in Little Rock.
We spoke with a criminal justice professor at the University of Arkansas Little Rock about the problem.
He says it's uncommon to hear about family members killing each other, but when it does happen, the crime is usually not pre-planned.
It was late this Thursday night when police say 30-year-old Sean Johnson killed his father.
The victim's wife says her son attacked them with a knife.
Last December, Searcy police say a woman shot and killed her own mother after a fight in a Big Lots parking lot.
33-year-old Alexandria Williams is charged with first-degree murder.
Corporal Steve Hernandez with Searcy Police said, "Any time you have family members taking other family members lives, that's a bad deal."
In another shooting, five months ago, Little Rock police say 25-year-old Justin Bledsoe killed his grandfather.
And, last year in Ashley County, Jewel White pleaded guilty to the the murder of her mother.
Dr. Jeffrey Walker, from the UALR Criminal Justice Department, said, "Anytime you have that kind of violence in a family, it's a little scarier even than stranger violence."
Dr. Walker says there's usually an underlying issue -- with family murder -- like addiction or mental illness.
Many times however, he says the motive is unknown.
He said, "Could be that they just have a rage. You get into an argument and they get access to a gun or knife or something like that."
While the reasons for family murder may be different in every case, Dr. Walker says the remorse the person feels is generally the same.
He described it as, "Like, I don't know what I did. I wish it had been me kind of thing."
Dr. Walker also said the weapon used in most family murders is a gun because this crime typically isn't planned out and it's just a quick moment of rage.
As far as signs that may let parents know their son or daughter could become violent, Dr. Walker says there may not be any.
He said it's important to be aware of drug and alcohol addiction and mental illness though, as again, those could be underlying issues.
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