In 2007, a fisherman discovered an infant’s remains in a sealed container in a waterway near Sacramento. Efforts to identify the child, who had died of blunt force trauma, were unsuccessful, and the investigation into the killing stalled for a dozen years.
Then, in October 2019, investigators were able to identify the 1-month-old-baby, Nikko Lee Perez, using a new technique of DNA comparison.
On Monday, the authorities announced that the baby’s father, Paul Perez, 57, of Delano, Calif., who is already serving time in prison on unrelated offenses, had been arrested on charges that he tortured and murdered Nikko in 1996. They also said that he had killed four other infant children of his in a similar manner from 1992 to 2001.
“In my 40 years of law enforcement, I cannot think of a case more disturbing than this one,” Sheriff Tom Lopez of Yolo County said in a statement. “There can be no victim more vulnerable and innocent than an infant, and unfortunately this case involves five.”
Mr. Perez was charged with five counts of first-degree murder, each with attached special circumstances for torture and lying in wait. He was also charged with four counts related to assaulting a child under the age of 8 with force likely to result in death.
His arrest came days before he was to be released from Kern Valley State Prison. A convicted sex offender, Mr. Perez had been incarcerated there since 2010 on offenses including vehicle theft and possession of a deadly weapon.
If convicted of the murder charges, Mr. Perez could face a penalty of life in prison without the possibility of parole, or the death penalty, District Attorney Jeff Reisig said at a news conference on Monday. He added that it would take months for prosecutors to decide whether to seek capital punishment.
The discovery leading to the arrest occurred nearly 13 years ago, on March 29, 2007, when the decomposed remains of a 1-month-old baby — who was wearing a diaper and wrapped in a Winnie-the-Pooh blanket — were found in a metal cooler in a waterway about four miles east of Woodland, Calif., a northwest suburb of Sacramento. The cooler had been weighed down with pieces of metal rotors, a brick and numerous U-shaped metal pieces, according to an autopsy report.
But efforts at the time to identify the victim failed and, with no new information, the case went cold.
“As you can imagine, having an unsolved death of a child in our files has haunted my agency for years,” Sheriff Lopez said at the news conference. “But what began as a single unsolved homicide has become something much more.”
In October 2019, the state’s Bureau of Forensic Services, the scientific arm of the attorney general’s office, and the Yolo County Coroner’s Office used a new DNA comparison technique to identify the infant.
Previously, the Missing Persons DNA Program, housed within the California Department of Justice, had uploaded the infant’s DNA to be checked weekly against the federal Combined DNA Index System, which tracks data recovered from crime scenes, said Edward Medrano, the department’s chief.
“When those searches failed to yield results, we expanded our search to look for kinship-based matches,” Mr. Medrano said. “Using DNA technology developed by scientists at the California Department of Justice, we were able to create a list of potential siblings and parents of the victim.”
This was the first time that the kinship-based search using the existing database technology had ever been used in a missing person investigation, said Sarah Lovenheim, a spokeswoman for the attorney general.
With this new information, the investigators were able to connect the infant to Mr. Perez and, through investigating, learned that Nikko had at least four siblings who had suffered the same fate, Sheriff Lopez said.
All five, born in California, are believed to have been murdered as infants when they were younger than 6 months old: Kato Allen Perez, born in 1992; Mika Alena Perez, in 1995; Nikko Lee Perez, in 1996; Nikko Lee Perez, in 1997; and Kato Krow Perez, in 2001.
Before the authorities linked Nikko’s death to Mr. Perez, they had been aware of the death of only one of the other four children: Kato Allen, Lt. Matthew Davis of the Yolo County Sheriff’s Office said. He said that the authorities had learned of Kato’s death when it happened, but would not provide any further details on the circumstances of that death.
The authorities learned of the deaths of the three other infants as part of the current investigation, he said. They were never reported missing and their remains have not been found.
Officials declined to comment on whether Mr. Perez had other children or if the victims came from more than one mother.
“As seen in other cases around the nation,” Mr. Reisig, the district attorney, said, “the science and power of DNA has shown that monsters and killers cannot hide forever any longer.”
Sheelagh McNeill contributed research.
