Authorities are still trying to unravel the events that led to the killing of a Roanoke mother and the arrest of her two teenage children and another youth in the crime.
Jennifer Bailey, 17, her 16-year-old boyfriend, and her 14-year-old brother are charged with capital murder in the slaying of Susan Bailey, 43.
Her body was found in a pool of blood at her home on Sept. 28.
"It takes a lot of rage to kill your mother or father," said Dr. Charles Ewing, a forensic psychologist at the State University of New York at Buffalo. "It's the ultimate taboo in our society."
Parricide - the murder of a parent - is also among the rarest of crimes.
"It's not common at all," said Dr. Ashley Blackburn, a professor of criminal justice at the University of North Texas. "That's why these crimes make such a splash, because they shock the public conscience."
Of the 14,831 homicides reported nationwide last year, an estimated 201 victims were parents killed by their children, according to Federal Bureau of Information statistics.
Jennifer Bailey has declined interview requests and said little to police since her arrest.
The Tarrant County medical examiner's office determined that Ms. Bailey died of multiple stab wounds to her neck.
That type of up-close attack is much more personal than shooting someone, said Dr. Ewing, who has interviewed dozens of youths accused of parricide and written a book on the subject.
"To stab someone to death requires a lot more energy, investment and a lot more rage," he said.
A few days before the killing, police came to the Bailey house looking for Jennifer's boyfriend, who had been reported as a runaway by his father.
Officers witnessed a heated argument between the mother and daughter. Ms. Bailey, who friends have said did not approve of the boy, apparently became upset when she learned that Jennifer was still seeing him.
If that argument ultimately led to Ms. Bailey's death, it might seem irrational to many.
But mounting evidence suggests that adolescents are wired differently from adults, said Dr. Phillip Lyons, a criminal justice professor at Sam Houston State University in Huntsville.
He said the prefrontal cortex - the area of the brain that governs impulsivity, long-term planning, and the ability to foresee consequences of actions - takes time to fully develop.
"Adulthood is not an event that happens on your 17th or 21st birthday," Dr. Lyons said. "It's a process that begins in adolescence and doesn't finish until the late 20s."
And while these types of crimes can be committed by adolescents who are mentally ill or who have endured years of abuse, parents can also become murder victims when their children are unable to get something from them, such as money, control or freedom.
"The child sees the parents as an impediment to something the child wants - and they want to get rid of that impediment," said Dr. Ewing, who calls these "instrumental killings."
Such slayings, though rare, are not new to North Texas.
Last year in Collin County, Paul Edward Hancock, 24, was imprisoned for 15 years for fatally stabbing his 62-year-old mother after she accused him of stealing her money and prescription pills.
The woman's body was found floating in Lake Ray Hubbard.
In 1995, Jennifer Nicole Yesconis was found guilty by a Tarrant County jury of killing her father and stepmother in their Mansfield home.
Prosecutors said she asked her boyfriend and a friend to commit the double homicide so she could collect on a $133,000 life insurance policy.
In 1996, another Tarrant County jury convicted Dorothy Marie Robards of poisoning her father by stirring barium acetate into his refried beans. Steven Robards was divorced from his daughter's mother at the time of his 1993 death.
After her arrest, Ms. Robards - who was 16 and lived with her father when she committed the murder - told police that she did it because "I wanted to be with my mom so bad."
