In separate and horrific incidents, a mother and father in different parts of the United States were accused this week of killing their children in two apparent group murders that shocked their respective communities.
The killings appear to be the most recent in a disturbing series of family-related murders, sometimes murder-suicides, which criminologists and forensic psychiatrists call familicides.
A woman found in her Washington, D.C., home with the decomposing bodies of four girls was charged Thursday with four counts of first-degree murder. Banita Jacks, 33, who is thought to be the mother of the four youths, who ranged in age from 5 to 17, faces up to life in prison if convicted. Jacks told police the children were "possessed by demons" and had died in their sleep, court documents say, according to the Associated Press.
In the small town of Bayou La Batre, Ala., a father was charged with four counts of capital murder Wednesday for allegedly throwing his four kids, all age 3 and under, off a bridge. Rescue workers said the children could not have survived and they're attempting to find the bodies.
Police say Lam Luong, 37, confessed to the crime, though his attorney said that Luong denied killing them and he was coerced by police into making a false confession The attorney, Joe Kulakowski, told ABC News that he believed the children were not, in fact, thrown off the bridge and were still alive.
Last year, ABC News spoke with several medical and forensic experts about familicides. They said then that men and women are often motivated to kill their children for different reasons.
Unlike men, who often are driven to familicide by feelings that they have failed to adequately provide for their kids, women often kill their children out of a delusional sense of altruism.
Authorities in Washington said they were operating on the assumption that Jacks was the mother of the four girls whose bodies were found in her house, though they did not have conclusive proof. Marie Pierre-Louis, the medical examiner, said the bodies were probably in Jacks' house more than 15 days, "based on the insects that were found there."
The cause of death was unclear, though Pierre-Louis said at a news conference today that it appeared that the eldest girl may have been stabbed and that the others may have been asphyxiated.
Jacks faces four murder charges and up to life in prison if convicted. She was ordered held without bond on Thursday.
"I don't think anyone in the city can remember a case involving this many young people who have died in such a tragic way," Mayor Adrian Fenty said.
In the Alabama case, police think Luong threw the children, who ranged in age 4 months to 3, from the bridge after an argument with his wife, The Associated Press reported. Luong had a crack cocaine possession charge pending in Georgia, and his wife's brother-in-law described Luong as a drug addict, according to the AP.
Some men and women who kill their children, forensic psychologists and criminologists told ABC News, tend to be severely depressed or psychotic and do not simply "snap" but usually have long histories of mental illness.
In June, wrestler Chris Benoit made headlines when he killed his wife, his 7-year-old son and himself in the family's Fayetteville, Ga., home.
Benoit's wife, Nancy, 43, and son, Daniel, were each found in different rooms and were believed to have been killed days before the wrestler took his own life.
Less than a week before the Benoit killings, New Jersey engineer Thomas Reilly and California businessman Kevin Morrissey each decided to kill their children and then themselves.
Reilly, 46, drowned his two young daughters, ages 5 and 6, in the bathtub of their Montclair, N.J., home before hanging himself from the attic rafters.
Morrissey, 51, shot his wife and two daughters in a parked car at a popular park near Berkeley, Calif., before turning his .357 handgun on himself.
Police investigating the deaths of Morrissey and his family said they found a note in which he said he was distressed over the family's financial situation.
Morissey ran a skin-care clinic with his wife, Mamiko Kawai, 40. The couple's two daughters were Nikki Morrissey, 8, and Kim Morrissey, 6.
Phillip Resnick, a psychiatry professor at Case Western Reserve University, said Morrissey may have been "severely depressed and believed his family was similarly miserable. He was ending the entire family's pain."
"Money is often an issue. The man sees himself as a breadwinner and may feel like he has to take the whole family out with him," Resnick said.
Local, state and federal agencies do not specifically track familicides, and discrepancies in the way the crimes are classified make getting an accurate count difficult.