Accused Killer’s Mother Arrived in Harrisburg Right After Murder, Victim’s Mom Says

Hours after 41-year-old Jonathan Gatto called 911 to report a bedroom fire at his Harrisburg home, his mother arrived in Harrisburg from California, according to emergency custody filings obtained by PennLive.

Investigators say Gatto strangled his estranged wife, 41-year-old pediatrician Julia Pederson, before intentionally pouring an incendiary fluid on a space heater to ignite the blaze on October 10. Gatto now faces charges of first-degree murder and arson.

The Suspicious Arrival and Emergency Custody Filing

Pederson’s mother, Kathleen Pederson, wrote in an emergency custody petition that the paternal grandmother, Joyce Gatto, “suspiciously” arrived in town very quickly from San Mateo following the killing. Kathleen Pederson asserted that Jonathan Gatto signed a temporary custody document naming his mother as a temporary guardian because he knew he would be arrested for the murder.

Two days after the discovery of the killing, and before the coroner ruled Pederson’s death a homicide, Jonathan Gatto hired a lawyer to draw up the standby guardianship paperwork. The document designated Joyce Gatto to care for the couple’s 7-year-old daughter for 60 days in the event of his incarceration or death.

Poisoning Suspicions and Prior Threats Involving Argentina

Before her death, Julia Pederson suspected she was being poisoned after weeks of her husband dropping off unrequested drinks at her office, sharing her fears with her best friend, mother, and sister. She had planned to have a blood test Sunday Oct. 11.

In her court filings, Kathleen Pederson expressed urgent concern that Joyce Gatto would remove the child from the jurisdiction of the court. Kathleen noted both Jonathan and Joyce Gatto have dual citizenship and real estate in Argentina, and Kathleen Pederson stated that Jonathan Gatto had previously threatened to abscond to Argentina with the girl against Julia Pederson’s wishes while she was alive.

Dauphin County Court Hearings and Custody Battle

Dauphin County Children and Youth Services held a hearing Oct. 15 and awarded Joyce Gatto temporary custody based on her son’s designation while mandating that she keep the child within Dauphin County. Both grandmothers filed competing custody paperwork the following day.

While Joyce Gatto stated in court records that the 7-year-old girl indicated a preference for her, Kathleen Pederson countered that the child lacked the maturity to state such a preference and likely was coached by Jonathan or Joyce Gatto. Both grandmothers asserted they previously lived with the family and helped raise the child after the couple moved to Harrisburg in 2025 following time spent in Argentina and California.

Unresolved Rulings and Pending Judicial Review

It remains unclear when a judge will issue a ruling on the motions filed by the two grandmothers in Dauphin County. Legal experts note that child custody determinations in Pennsylvania prioritize safety factors, including the child’s trauma exposure, access to extended family, and whether visitation with an incarcerated parent poses psychological risks.

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