A woman whose car plunged into a lake from a dead-end road told a sheriff she tried to rescue her three sons but lost her grip on them in the water and they drowned, according to a newspaper report.

The sheriff's office said Monday it was conducting interviews and checking her story.

The boys, ages 8, 7 and 2, were recovered from Lake Brewer after the car went in the water at about 3:30 a.m. (0830 GMT) Sunday, in a rural area of central Arkansas, and they were pronounced dead at a hospital. Conway County officials had not released their names Monday morning.

The woman said she tried to pull the boys to safety from the car but lost her grip on them, Conway County Sheriff Mike Smith told the Arkansas Democrat-Gazette newspaper of Little Rock.

Smith said no charges had been filed, and said investigators are working to verify the mother's account.

"We're going to run back through what she said," Smith told The Associated Press. "We want to make sure we do a good job on that."

Autopsy results were pending for the boys.

The car was traveling on Old Highway 92, known as Johnny Walker Road, that dead-ends at the lake. The state highway was relocated years ago when Cypress Creek was dammed to form the reservoir.

A warning sign directs motorists to turn left at the bottom of a hill but the road itself goes straight to the edge of the lake, where there is no other warning sign.

Smith said many people in Conway County, about 30 miles (48 kilometers) west of Little Rock, use the old highway to back boats into the lake, which is a state wildlife management area. The reservoir serves as the main drinking water source for the nearby city of Conway.

It wasn't clear Monday morning whether the state or Conway County was responsible for maintaining signs on the old route.

Smith declined to say if deputies conducted a field-sobriety test on the mother or drew any of her blood.

"We'll do our investigation and we certainly will turn everything over to our prosecuting attorney," Smith said.