FRANKLIN COUNTY • The mother of an 8-year-old boy killed in a car crash Monday has been arrested because authorities believe she was driving while intoxicated.

Heather M. Miller was arrested on suspicion of involuntary manslaughter after the boy's death, the Missouri Highway Patrol said. The patrol is also seeking three counts of endangering the welfare of a child, because three other children were in the car. Charges are pending.

The Missouri Highway Patrol identified the boy as Tyler Freihaut, 8, of Lonedell.

Tyler was not wearing a seat belt as he rode in a 1999 Oldsmobile Bravada driven by Miller, 31, of Lonedell, authorities said.

Just before noon on Monday, Miller was driving north on Missouri Route FF in Franklin County with Tyler and three other children, who are Tyler's half siblings, in the car.

The SUV went off the right side of the road. Miller steered to the left and overcorrected, causing the car to overturn south of Old Mount Hope Road.

The three other children — two girls who are 1 year old and a girl who is 2 years old— were strapped into car seats and were not injured in the crash, the patrol said.

Miller was hurt in the crash, though the patrol described her injuries only as "moderate." She was not wearing a seat belt. She was arrested within 15 minutes of the crash, then released to the staff at St. John's Mercy Medical Center in Creve Coeur, said Cpl. Jeff Wilson of the Missouri Highway Patrol.

Wilson said the case will be turned over to the Franklin County prosecutor for charges.

Tyler was a third-grader at Lonedell Elementary School. "He was very smart and very athletic," his grandmother Margaret Freihaut said. "He was never afraid to try anything."

A fund has been set up to help pay funeral expenses for the boy. Contributions to the Tyler Freihaut Memorial Fund can be made at any U.S. Bank location.