The 7-month-old baby boy died from his injuries

A California mom is accused of dropping her 7-month-old baby to his death from a hospital parking structure.

An Orange County Superior Court judge postponed the arraignment for Sonia Hermosillo, 31, until September 30 at the request her court-appointed public defender, Charles Hasse.

Hermosillo, who has been kept under a suicide watch at Orange County Jail in the days following her arrest last week, was brought into court in a wheelchair and spoke little during the brief hearing.

Hermosillo is charged with murder and assault on a child causing death or great bodily injury. She faces a maximum of 25 years in prison if convicted at trial.

The arraignment had initially been scheduled to take place on Thursday but was postponed after a doctor who evaluated Hermosillo at the jail found her mentally unfit to go to court.

Prosecutors say Hermosillo last week dropped her 7-month-old son from the fourth floor of a parking garage at Children's Hospital of Orange County, where the boy had been treated for birth defects.

He later died from his injuries.

Hermosillo, who has two other children, was being held on $1 million bond and was also subject to a U.S. Customs and Immigration Enforcement hold while authorities determine if she is in the country legally.

Her husband, Noe Medina, has told reporters his wife suffered from severe postpartum depression and had trouble accepting her son because of his health problems.

But Orange County Deputy District Attorney Scott Simmons, the lead prosecutor in the case, has said she "knew what she was doing" when she pushed her baby to his death from the parking garage.

Simmons said evidence would show that after pushing her baby to his death, Hermosillo went inside the hospital to validate her parking before fleeing the scene.

She was arrested after a witness who saw the boy falling through the air called 911.

Police spotted Hermosillo in her car, which was captured on a surveillance camera leaving the parking structure.