San Bernardino County sheriff's deputies responded Saturday morning to the 35000 block of Persimmon Avenue in Yucaipa to a report of a six-month-old child not breathing.
The child was transported to a local hospital and was pronounced dead later that evening.
Detectives investigated the girl's death and then arrested her father, Alfonso Ornelas, 28, for murder and assault on a child causing great bodily injury/death.
No additional details on the circumstances of the infant's death were released.
Anyone with information is asked to call Detective Julius McChristian at (909)387-3589. Callers can provide anonymous information to WeTip at (800)78-CRIME or www.wetip.com.