Significant trauma found during hospital treatment prompted child-abuse and homicide detectives to investigate the 7-month-old girl’s death.
SAN DIEGO, Calif. — The official cause and manner of death remained pending Wednesday for a 7-month-old Mission Valley girl whose injuries prompted a homicide investigation and the arrest of her father, authorities said.
The San Diego County Medical Examiner’s Office is working to determine how the infant died after she was taken to Rady Children’s Hospital late Monday. San Diego police said medical personnel found significant trauma while evaluating and treating the child, leading detectives from the department’s Child Abuse and Homicide units to investigate.
The investigation began after the girl’s father, 38-year-old Rafael Santos, called 911 at about 6:34 p.m. Monday, Sept. 21. He told authorities that his daughter was unresponsive and not breathing at the family’s apartment in the 1400 block of Hotel Circle North in Mission Valley West.
Police officers and San Diego Fire-Rescue Department paramedics responded and performed emergency medical treatment before the infant was taken by ambulance to Rady Children’s Hospital. She died shortly after midnight Tuesday, according to police.
Investigators said preliminary findings indicated that the child died at the hands of another person. Santos was arrested and booked into San Diego County Jail on suspicion of murder and child abuse causing death. Authorities have not publicly described the specific injuries, when they occurred or what evidence led detectives to arrest Santos.
The medical examiner’s determination remains an important unresolved part of the case. A cause of death identifies the injury or medical condition responsible for a death, while the manner of death classifies the circumstances under which it occurred. Police had not announced those findings as of Wednesday.
The infant’s identity had not been publicly released. Investigators also had not disclosed whether anyone else was inside the apartment before emergency crews arrived, and no additional arrests had been announced. Police have not released a suspected motive.
Santos remained in custody without bail, according to published reports citing authorities, with an arraignment scheduled for Thursday afternoon. The allegations against him have not been proven in court, and formal charging decisions are handled through the criminal justice process.
The investigation remained active Wednesday as detectives worked with the Medical Examiner’s Office to establish the circumstances surrounding the child’s death. Police continued seeking information from anyone who may have knowledge relevant to the case.
Author note: Last updated September 23, 2026.