The death of a 2-month-old baby in April was a homicide, the San Jose police department announced Tuesday.
The unnamed newborn was reported dead April 4 at a hospital, prompting police to interview the baby's parents and collect other evidence, authorities said.
"The motive and circumstances surrounding the incident are under investigation," police said in a statement.
The baby was malnourished and had signs of trauma to the head, officials said.
The Santa Clara County Chief Medical Examiner-Coroner's Office earlier this month gave police "final medical reports and autopsy results for the victim, citing the manner of death as homicide."
Police did not say whether anyone had been arrested or if authorities were looking for suspects.