LOS ANGELES (CBSLA) — A California man rang in the New Year by leading police in South Dakota on a 100-mile-per-hour chase that ended with a gruesome discovery for officers.

When Tosten Walsh Lommen’s SUV hit a spike strip and landed in a ditch, he fled the scene. State troopers found the body of his 58-year-old mother Michelle Walsh wrapped in a blanket in the back seat, according to the Pennington County Sheriff’s Department.

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Police don’t know how or where Walsh, who is from Palm Springs, died or if her son was the one who killed her.

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“As a result of this investigation it’s certainly something we’re looking into,” Sgt. William Hutchinson, of the Palm Springs Police Department said. “Until we can find the exact cause of death and get that information, we won’t have all that information at this time.”

The only clue so far is that the son had his mother’s credit cards and prescription bottles in the car.

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Lommen, 30, is also accused of being drunk while leading police on the 45-mile chase through South Dakota.