According to Los Angeles County sheriff's investigators, Aiden Lopez was under the care of his babysitter Brittany Ingrassi, a long-time friend of Aiden's father, on March 22.
Around 5:20 p.m., deputies and paramedics were called to the 43400 block of Gadsden Avenue on a report of a baby not breathing.
Aiden was found with serious head trauma and bruising to the upper torso, officials said. He was transported to an area hospital, where he died of his injuries four days later on March 26.
Detectives arrested Ingrassi, 30, on Tuesday. She was charged on Thursday with one count each of assault on a child becoming comatose/paralyzed and child abuse with an allegation that the defendant personally inflicted great bodily injury on the victim who was under the age of 5, the district attorney's office said.
Sheriff's officials said additional charges are expected to be filed. Ingrassi's arraignment was scheduled for April 15. She was being held on $1 million bail.
If you have any relevant information, you're urged to contact the Los Angeles County Sheriff's Department's Homicide Bureau Detective Baljet or Sgt. Ewing at (323) 890-5500. You can also provide anonymous tips by calling Crime Stoppers at (800) 222-TIPS.