A South Dakota Highway Patrol trooper discovered Marguerite Engle, 45, on Dec. 1 passed out behind the wheel of a delivery truck reported stolen in Rapid City.

Her blood-alcohol level was almost nine times South Dakota’s legal limit of .08 percent.

Checks with local and state labs where blood-alcohol levels are tested suggest Engle’s reading may be the highest ever recorded in South Dakota, Sondreal said.

Sondreal said a state chemist recalled a sample that tested .53, but nothing higher, in his more than 30 years on the job.

Dr. Robert Looyenga, who recently retired from the Rapid City Police Department’s forensic laboratory, told Sondreal that the highest blood-alcohol sample he tested measured .56 percent.

Sondreal’s research indicates that a blood-alcohol level of .40 is considered a lethal dose for about 50 percent of the population.

“Engle’s was almost double that,” Sondreal said.

After she was found, Engle was hospitalized and freed on bond.

She failed to appear in court on Dec. 15, but Sturgis police located her Monday evening in another stolen car sitting in a ditch along S.D. Highway 34 near Fort Meade.

Engle was arrested for second offense driving under the influence and taken to jail.

Engle made her initial appearance in Meade County magistrate court Tuesday. She is being held without bond.

Sondreal said Engle has been living in a hotel after recently moving here from Minnesota.  Engle is most likely facing charges in Pennington County since both vehicles were stolen in Rapid City, Sondreal said.