Officers responded at approximately 11:35 a.m. Monday to the 1400 block of Lynoak Drive, near Foothill Boulevard, regarding a medical emergency, according to the Claremont Police Department.
Police said the responding officers determined, upon investigating, that an infant had been thrown to the floor by a juvenile at the home, prompting the response of Los Angeles County Fire Department paramedics.
The infant was taken to Pomona Valley Hospital Medical Center for emergency medical treatment before being transferred to Children's Hospital of Orange County, where she later died as a result of her injuries.
The suspect, a male juvenile, was taken into custody at the scene and taken to the Claremont Police Department Jail, where he was booked. His name was not released due to his age.
He was being held at the Los Padrinos Juvenile Hall on suspicion of murder and is expected to appear in court Thursday to be arraigned, police said.
Anyone with information regarding the case was urged to call the Claremont Police Department at (909) 399-5411.