ORLANDO, Fla. -

The Orange County mother of a 3-year-old girl who died last week is now under medical observation after being charged with first-degree murder, according to jail officials.

Maryanne Schwartz, of Orlando, was originally arrested Wednesday on child abuse charges in connection with her other child. The first-degree murder charge was added late Wednesday night.

Schwartz was expected to have her first court appearance Thursday morning, but it was postponed because she's under medical observation.

A medical examiner determined the death of Schwartz's 3-year-old, Yeliani Schwartz-Ojeda, was a homicide, adding the girl's condition was not consistent with a hit-and-run crash, which is how Schwartz said her daughter died.

Schwartz told investigators the girl was hit by a car Saturday and the driver fled the scene.

A judge ruled Tuesday that Schwartz's 2-year-old son will stay in state custody, but Schwartz could have supervised visits.  Medical workers at Arnold Palmer Hospital alerted the Orange County Sheriff's Office that the child had "multiple bruises on his body that were not consistent with normal child activities."

The medical examiner found Yeliani died of blunt-force trauma but couldn't confirm she was hit by a car. Officials also said they found evidence of bruising on the child and she was malnourished.

The three kids of Schwartz's partner and roommate, Vanessa Morales, will stay with their grandmother, and Morales will only have supervised visits.