COLUMBIA -- The mother of a toddler missing since Thanksgiving is pregnant and mentally ill and should be released from jail because she needs medical care, the woman's attorney argued in court papers filed this week.

Hemphill Pride II said Zinah Jennings has been ordered to have treatment for her mental illness for a year and has been told to take Risperdal, which is used to treat symptoms of schizophrenia.

He also said she needs prenatal care.

On Thursday, dozens of federal, state and local police agents and cadaver-dog teams searched for more than four hours in a county in the central part of the state for the Amir, who was 18 months old when he disappeared.

Columbia police spokeswoman Jennifer Timmons said officers scoured an 8-mile radius near a small rural church in Richland County but found no evidence of the boy.

Jennings, 22, has been in jail since late December, when Columbia police said they arrested her for lying about the whereabouts of her son.