ORANGEBURG, S.C. - A South Carolina mother who claimed her children drowned when their car careened into a river was charged with murder Tuesday after authorities said she confessed to suffocating the two toddlers to be free of them and then faking the accident.

Shaquan Duley, 29, told investigators she was distraught about money troubles and unemployment, said Orangeburg County Sheriff Larry Williams. He said Duley told them she killed the boys - 2-year-old Devean C. Duley and 18-month-old Ja'van T. Duley - after arguing with her own mother about how she was raising the children.

"She truly felt, if I don't have these toddlers, I can be free," Williams said at a news conference.

Officials said they were unable to locate the children's father, who did not live with the family. Duley has another child, a 5-year-old girl, who was now with the grandmother.

Duley's mother declined to comment when approached at her home.

The state agency responsible for child welfare in South Carolina said it has had no involvement with Duley.

The Highway Patrol was notified around 6:15 a.m. Monday that a woman needed help getting her children out of a car. Duley, who did not have a cell phone, had walked some distance down the country road by the boat landing and flagged down a passing motorist to call the Highway Patrol.

Later that morning, authorities pulled Duley's Chrysler sedan from the North Edisto River in Orangeburg, some 35 miles south of Columbia, the state capital. The two boys were still strapped into their car seats.

Duley said she'd had an accident and walked to get help. But almost immediately, Williams says authorities became suspicious of the young mother's story. There were no skid marks on the roads leading to the water, and no obvious signs of a crash.

"We felt that the story she was telling us wasn't factual," Williams said.

Deputies interrogated Duley throughout the night, asking her questions about her family. Eventually, Williams said, Duley broke down and admitted to deputies that, strained by the responsibilities of being a mother, she had killed her sons, driven their bodies to the water and forced the car in.

"I think she was fed up with her mother telling her she couldn't take care of the children, or she wasn't taking care of the children and just wanted to be free," Williams said.

After that argument, Williams said Duley checked into a motel in Orangeburg with the two youngest children. In that motel room, Williams says the mother put her hands over her children's' mouths and suffocated them.

"I believe there was an emotional rush," Williams said at a news conference. "I think that the opportunity presented itself and she reacted to whatever condition presented itself for her to get rid of the children."

Duley was to be arraigned Wednesday. Authorities were not sure if she had an attorney.