Samantha Harper, 25, of Smyrna has been charged with two counts of especially aggravated child abuse, The (Murfreesboro) Daily News Journal reported.
Police said Harper placed 2-year-old Savannah Marise and 3-year-old Daniel Marise in the car outside her home Thursday, then went inside and went to sleep. Officers responded to a 911 call about 3:45 p.m. from Harper, made at a neighbor's house.
Harper initially told a 911 dispatcher: "My kids got outside and they got in my car, and I think they're both dead now." She later changed her story during questioning, WSMV-TV Nashville, Tenn., reported.
The dispatcher asked how long the kids were in the car, to which Harper replied she didn't know. The dispatcher pressed her further, asking when she last saw them. "I want to say it was between 11 and 12," she replied.
Responding officers found both children lying dead on the ground next to the car. One officer asked Harper again how long the kids were in the car.
"I don't know!" she responded. "They took a nap, I took a nap, and I guess I must've been asleep for some time! I don't know how they got out."
Harper was jailed in lieu of a $200,000 bond. Records show she has no criminal history, though a child neglect report was filed against her with La Vergne police last September.
Harper's home has since been condemned after responding officers found it to be uninhabitable.