According to coroner's officials, the 4-month-old girl died at Downey Community Hospital on New Year's Eve from malnutrition and blunt force trauma.
The investigation began after a medical emergency call to an apartment on the 8400 block of East Imperial Highway. Police found the infant non-responsive and efforts to revive her were unsuccessful.
The parents were placed under arrest. Their names have not been released.
If you have any information about this case, you're urged to contact the Downey Police Department at (562) 904-2308 or Crime Stoppers at (800) 222-TIPS.