A mother was charged with murder after admitting she suffocated her two toddler sons before strapping them into her car and pushing it into a river to pretend they had died in an accident

Orangeburg County Sheriff Larry Williams said Shaquan Duley, aged 29, from South Carolina, had admitted in a police interview that she smothered to death her sons.

Devean was aged 2 years, and Ja'van was aged 18 months.

"She was a mother that was unemployed. She had no means of taking care of her children," Williams said.

"The responsibility of being a mom was a bit much for her.

"She was living with her mother. I believe she was fed up with her mother telling her that she couldn't take care of the children, or she wasn't taking care of the children.

"She just wanted to be free," the policeman said.

He said Duley had checked into a motel after a fight with her mother and drove around with the dead children before rolling the car into the river.

"The children were dead when they were placed into the water. By taking them to the river, she believed she could stage an accident," he said.

Williams said Duley initially told investigators at the scene she had had an accident. But there were no car skid marks, Duley's clothes were not wet and her demeanor was calm, he said. "She didn't show any remorse," he said.

Duley also had a 5-year-old daughter who was unharmed.

In 1994, another South Carolina mother, Susan Smith, of Union County, was arrested over the deaths of her sons, Michael, 3, and Alexander, 14 months.

Smith initially said a stranger carjacked her vehicle with the children and a massive search ensued.

But about a week later, investigators pulled Smith's car from the bottom of a lake near the town of Union with the two bodies strapped inside.

Smith was convicted of the murders and is serving a life sentence.