There are chilling new details about a New Jersey mom charged with killing her two children being revealed in 911 calls.

The initial call came from a man who found Yuhwei Chou, 36, inside her car which was off the road in Hillsborough. He tells the dispatcher that she was tied to the steering wheel and had duct tape on her head. "I don't think she's in a good mental state," he's heard saying on recordings obtained by MyCentralJersey.com

The panic rises in his voice as he then describes the children in the back seat. "The baby is not responsive. Hurry, please hurry," he pleads. He then tells the 911 operator, "I think she killed the baby."

Police say Chou had restrained both of her children in the back of the vehicle. Eleven-month-old Paul and 7-year-old Samantha. Both were dead.

The caller then breaks down into tears. Sobbing, he tells the dispatcher, "I don't think this is very good."

When she was arrested by police, investigators say Chou told them she killed her kids a day before they were found on Nov. 9, and had been plotting their deaths for a week.

She was detailed, they say, in her confession. She explained how she drove to Wawa for lunch, then went to a hardware store to buy duct tape and zip ties. Chou then described binding her children's hands, placing duct tape over their mouths and how she suffocated them with her bare hands.

What she has not said, however, is why she did it.

Chou remains jailed on murder charges. A judge has ordered her to remain incarcerated pending the outcome of her case.

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