In Raijon Daniels' short eight years of life, his Richmond mother, Teresa Moses, beat, starved and washed him with household chemicals and high-pressure hoses.
In 2009, Judith Williams drove her 16-year-old son to the top of Mt. Diablo State Park, shot him in the back and head and then turned the .357 revolver on herself.
And just last week, Ashley Newton, a young San Jose mother, was arrested on suspicion of fatally stabbing her 7-month-old son with a pocket knife in a Livermore park.
Maternal filicide -- mothers killing their own children -- is rare, experts say, but each time it occurs, the horrific crime raises the question: How could it happen?
"Mothers don't kill their children unless they are seriously disturbed," said Dr. Lanny Berman, executive director of the American Association of Suicidology in Washington, D.C. "I think it gets attention because, one, it's unfathomable and two, it's sensational and obviously the media reports on that. But it should be noted that this is not common. It is very rare."
Rare as it is, there's clearly something about the mother-child relationship that can go badly wrong. According to the Department of Justice, women commit only 14 percent of all violent crimes in the United States. But a recent study on filicide shows they commit nearly half of all parental murders.
A 2014 Brown University study analyzing 32 years of filicide arrests found there are about 3,000 instances annually in the United States where a parent kills a child.
Investigators have not released a suspected motive for Newton, only saying it was not a murder-suicide attempt. She was arraigned Friday at John George Psychiatric Hospital in San Leandro, where she was being held for an undisclosed "medical issue." She did not enter a plea.
Evidence at the scene suggested Newton may have been depressed, police said, and one witness who rendered aid to the mortally wounded infant said he could tell the mother, caked in blood, was in "a really bad place."
"If there is indeed no suicidal behavior on her part, then typically it's homicidal behavior associated with a psychotic break or postpartum depression," Berman said.
Studies and experts agree on one common factor when mothers commit such an unthinkable crime: extreme mental illness.
Dr. Phillip Resnick, an expert in maternal filicide and a co-author of a 2007 World Psychiatry study, reviewed psychiatric studies on mothers killing their children and found most had depression, psychosis, and suicidal thoughts. He identified five motives:
Recognizing the special nature of the crime, other countries have infanticide laws that reduce the penalty for mothers who kill their children. British law allows mothers to be charged with manslaughter rather than murder if they have a mental disorder. Women who are convicted of infanticide there often receive probation and mental health treatment referrals rather than incarceration, according to Resnick's report.
On Oct. 19, 2005, Lashaun Harris, who the week before told family members she was going to feed her three small children to sharks, traveled with her kids on BART to San Francisco, walked to the end of Pier 7 and threw her children into the Bay.
The 23-year-old homeless Oakland mother with a history of schizophrenia and other mental illness told police she heard voices telling her to throw her children into the water so they could reunite with God in heaven.
"What I learned with Lashaun Harris was she was a good mother and she wouldn't have killed her children without her mental illness," said Teresa Caffese, the former San Francisco public defender who represented Harris. "Heaven to her was a concrete place with basketball courts, buses, you name it."
"The system sometimes does not sufficiently help the mentally ill," she said.
A jury acquitted Harris of first-degree murder but found her guilty of three counts of second-degree murder. A judge declared her criminally insane and sentenced her to a psychiatric hospital where she will remain unless she regains her sanity.
Last year, Teresa Moses was released from Napa State Hospital after doctors determined she was no longer a risk to society.
According to a 2011 report by the Department of Justice that studied homicide trends from 1980 to 2008, 63 percent of all murdered children under age 5 were killed by a parent; 33 percent by fathers and 30 percent by mothers.
The United States has the highest rates of child homicide and when a young child is murdered, it is most likely a parent who did it, according to Resnick's research.
In the case of infanticides -- children killed under the age of 1 -- such as the Livermore case, Resnick's study found women perpetrators were often unemployed mothers in their early 20s. Newton has no job and is 23, police said.
Resnick also found that those rates increased with economic stress and social isolation and offenders also experienced psychiatric disorders. Newton is originally from North Carolina, but has lived in Fremont and San Jose with no other family in the immediate area, police said.
"Unless there's a really unusual circumstance, a mother doesn't kill her children," Caffese said of the Newton case. "I bet there were signs all along that were just missed."
Contact Matthias Gafni at 925-952-5026. Follow him at Twitter.com/mgafni.
Having thoughts of suicide or need crisis help? Here are some 24-7 numbers and chat rooms:
Crisis and Suicide: 800-833-2900; 800-273-8255; 800-SUICIDE; 888-628-9454 (Spanish)
Talk via chat room http://www.suicidepreventionlifeline.org