Updated

A lawyer for a woman charged with murdering her 7-month-old son by pushing him off a four-story parking structure said Monday his client appeared only marginally coherent and did not fully understand the charges against her.

Sonia Hermosillo, 31, arrived in Orange County Superior Court in a wheelchair and blue jail jumpsuit, with her hands cuffed to the chair and her feet shackled.

She agreed to postpone her arraignment until Sept. 30 so she could be evaluated by a doctor, said Chuck Hasse, her lawyer.

"She wasn't really able to comprehend the nature of the charges," Hasse told reporters after the hearing. "She knows that she's being accused of killing her child. She nodded in agreement to that, that she marginally comprehended that. It's very speculative as to what she understands and what she doesn't understand."

Her husband, Noe Medina, has said his wife suffered postpartum depression and didn't know what she was doing. He urged the public not to judge her.

Hermosillo was arrested a week ago after her 7-month-old son Noe Medina Jr. was spotted falling from the parking structure at Children's Hospital of Orange County. She was arrested hours later as she drove nearby.

The baby died Aug. 24 and Hermosillo was charged with murder and assault on a child with force likely to produce great bodily injury resulting in death. If convicted, she could face a maximum sentence of 25 years to life in prison.

Prosecutors contend Hermosillo was aware of her actions, asserting that before she dropped her son she removed a special helmet that he wore for a medical condition.

Scott Simmons, senior deputy district attorney, said he believed Hermosillo understood what happened in court, and that she was brought out in a wheelchair because it was easier for jail officials to transport her.

"When the judge communicated with her, she appeared to understand what he was saying," Simmons said after the hearing. "I think she understands what's going on."

Hermosillo has been in a medical ward since she was arrested. She is on suicide watch in a cell by herself and has been wearing a protective gown to prevent her from harming herself, authorities said.

She is being held on $1 million bail and also has an immigration hold.

Hermosillo appeared Monday in a courtroom inside the jail in Santa Ana. She was not fully visible to the public on television screens in a nearby viewing room.

During the brief hearing, Hasse told the judge his client "doesn't quite understand why she can't go home."

Afterward, he told reporters that he was able to meet with Hermosillo for the first time five minutes before the hearing. He said his first step would be to get his client seen by a doctor and added that her mental state would be central to his case.

"It's obviously going to be a psychiatric defense, obviously. It's not a whodunit. It's not a, you know, whether it happened ..." Hasse said. "It's really going to be what was going on in her mind at the time."

Medina told the Orange County Register newspaper that his wife was hospitalized for postpartum depression in June after she said she didn't want the boy.

The baby had been diagnosed with congenital muscular torticollis — a twisting of the neck to one side — and wore a helmet to help correct his plagiocephaly, also known as flat-head syndrome, the newspaper reported.

Simmons said he understands that the public wants to make sense of an unthinkable act. He believes Hermosillo's actions show she murdered her child, noting she drove all the way to the hospital — a familiar place — where she took the baby for physical therapy twice a week, even though he didn't have an appointment that day. He also said she validated her parking after pushing the baby off the structure.

"Nobody really wants to think of her as a killer. It's easier for people to think, well, she's got these postpartum blues," Simmons told reporters after the hearing. "I think the evidence is clear. It's going to show that she didn't want to take care of this baby. She wanted to kill this baby."