Harris County deputies responded to a 911 call on Thursday afternoon just before 4 p.m. in the 1700 block of Penmark Lane in Katy for an "unknown medical emergency."
Investigators at the scene would not say who made the emergency call.
The infant and her 4-year-old brother were under the care of their father, Sheriff Ed Gonzalez said Friday. He described the child's injuries as "severe."
At the scene, investigators revealed very little about the circumstances.
ORIGINAL REPORT: 3-month-old baby dead after being found with 'severe trauma' in Katy, Harris County deputies say
"There were physical injuries that deputies, as well as first responders, observed," Deputy Investigator Brandon Mills with HCSO's Special Victims Unit 'Crimes Against Children' division said. "Without getting into too much details about it, there were physical injuries."
The infant was airlifted to a hospital, where she died a short time later.
An autopsy will be conducted on the child's body, but results are pending.
ABC13 crews outside the home observed a man being put into the back of a deputy's car in handcuffs but were told he was not under arrest.
The family did not have a history with CPS, according to Melissa Lanford, who serves as a spokesperson for the Department of Family and Protective Services.
She said CPS is now investigating alongside law enforcement.
The 4-year-old boy who was home at the time and their 7-year-old sibling were placed in foster care, according to Lanford.
The family asked for privacy.
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