Familial DNA Cracks the Case
Once familial DNA testing revealed the connection between the deceased baby and Perez, details began falling into place.
Investigators discovered the baby boy had been born in Fresno, Calif., on November 8, 1996. They noticed several of the baby’s siblings also mysteriously disappeared, most before reaching 6 months of age: Kato Allen Perez and Mika Alena Perez, both born in Merced, Calif., in 1992 and 1995, respectively; another Nikko Lee Perez born in Fresno in 1997, and Kato Krow Perez born in Fresno in 2001. Only the remains of two of the five children have been found.
On January 6, 2026, Perez was found guilty of one count of first-degree murder and three counts of second-degree murder, plus one count of assault on a child under 8 with force likely to produce great bodily injury resulting in death. The jury found Perez not guilty of first-degree and second-degree of murder in the fifth homicide charge. The judge declared a mistrial on the fifth homicide charge after jurors could not reach a verdict on a count of involuntary manslaughter. A case enhancement for committing multiple murders was also included.
Perez faces life in prison without the possibility of parole, though his April 2026 sentencing has been delayed as his attorney seeks a new trial for Perez.
What Makes Paul Allen Perez's Case Unique
Fathers rarely commit infanticide, especially on a repeated basis.
“Neonatal infanticide would be killing the baby soon after birth, and that happens often with single and very young women. Sometimes they’re in a state of postpartum psychosis, other times they're just unprepared to have a child and have kept the pregnancy secret,” California-based clinical and forensic psychologist Dr. Nancy Kaser-Boyd tells A&E Crime + Investigation. “Filicide usually is committed by a father, and it's usually not multiple children. Usually, filicide is as a result of child abuse, like a child that was beaten or shaken and then dies.”
Dr. Eric Hickey, professor at Walden University’s forensic psychology doctoral program and author of Serial Murderers and Their Victims, echoes the extreme abnormality of Perez’s case.
“We've seen female serial killers who killed their babies over time, but for a man to do it, it doesn't make a whole lot of sense,” he tells A&E Crime + Investigation. “There was a reason he killed them between 4 and 6 months [old]—likely because he was done with him at that point.”
The fact that Perez escaped detection as long as he did can be traced to a few key factors: The murders were spread over the course of nearly a decade; the family—which consisted of Perez, his wife, Yolanda, and a surviving daughter, Brittany, born in 1990—moved from town to town often enough to make it difficult for outsiders to know about the children; and some of the babies shared the same or very similar names.
“He knew exactly what he was doing,” Hickey says. “He's street smart. He watches crime movies, he understands how to avoid police and move around so he wouldn't be found out. He’s very controlling. Certainly a predator, very definitely a sociopath, because he controlled his spouse.”
But Perez had other children he didn’t kill.
Perez’s first wife, Susan, testified that she left him and took their young children with her after he slammed a crowbar near the head of their then 3-year-old son. Brittany, Perez’s eldest daughter with second wife, Yolanda, testified against her father in court.
Perez’s wife, Yolanda—who plead guilty to child endangerment in 2022—testified that she was terrified of the violent Perez. She claimed he often isolated her from the babies, and that he disposed of one by putting the body in a dresser drawer and weighing it down with cement.
“The weird part is how he would take a baby into the bedroom, and she wouldn't be able to go in. We'd have to speculate why that was, but he was a registered sex offender,” Kaser-Boyd, a specialist in battered women syndrome, tells A&E Crime + Investigation. “On the surface, it looks like he is a sociopath—angry, lashing out. She was afraid to report because she was afraid of him.”
Hickey wonders why Perez kept the babies alive approximately four to six months before killing them.
“Failed maltreatment is one common type of killing children. They don't say outright they're going to kill them, but in the end, over time, the abuse ends up killing them,” Hickey says. “But he had this demonstrated streak of sadism and was probably aroused by the suffering of the babies—the crying and so forth. But in the end, he kills them, and he probably got off on that.”
The Psychology Behind the Crimes
“Often, a parent has limited coping resources and can't stand the crying,” says Kaser-Boyd, who’s worked on several cases involving child abuse and neglect. “But I think there must have been something else going on with [Perez]. It sounds like most were beaten to death or smothered. [Yolanda’s] testimony talked about seeing a [live] baby in the carrier, and then the next time she looked, the baby was dead.”
She says that abusers like Perez were usually abused themselves and grew into aggressive, angry adults.
Hickey’s research suggests Perez was sadistically satisfied by harming the babies, and that he likely would have gone on to abuse and kill additional infants if he hadn’t been arrested. “That’s why it's important to understand what makes violators tick, what got them there,” Hickey says. “That might help with future interventions and preventions.”
