CHICAGO (CBS) — A mother was under arrest and undergoing a mental evaluation Thursday night, after her 7-month-old baby was found with a serious head injury.

Earlier in the day, police found two older children alone in the same Pullman neighborhood apartment where the baby was later found.

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As CBS 2’s Charlie De Mar reported, the 7-month-old was found unresponsive with blunt force trauma to the head and was in critical condition at the University of Chicago’s Comer Children’s Hospital Thursday night.

At 1 p.m., Chicago Police were called to an apartment building on the 900 block of East 104th Street. Two children – a 5-year-old boy and a 7-year-old girl – were found wandering around the building.

Police couldn’t find their 7-month-old sister or their mother. The older children were taken to Roseland Community Hospital for evaluation.

“I see the lady in the street yelling for help, screaming,” said Lashaun Foster.

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Lashaun Foster lives in the building and recorded cellphone video of the disturbance outside her window.

“I don’t know if she’s in her right state of mind, but I feel bad for that lady,” Foster said.

Police and the Illinois Department of Children and Family Services returned to the building at 6:30 p.m. for a wellbeing check. That was when they found the mother and the critically injured 7-month-old inside.

Foster said the mother was screaming and not making sense. De Mar asked Foster what the woman was saying.

“She want to die, kill her; she had COVID; ‘Get back! Get back! She don’t know you!’ She said the police was against her,” Foster said.

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The mother was taken into custody and also taken to St. Bernard Hospital for a mental evaluation.

Charlie De Mar