Authorities in South Dakota have dropped local charges against a California man who they say was arrested with his mother's body found in the vehicle he was driving.

The procedural move by prosecutors clears the way for Tosten Walsh Lommen, 30, to be returned to California to face a murder charge in that state, the Capital Journal reported.

Authorities allege Lommen killed his mother, Michelle Walsh, 58, sometime around Dec. 30 while the two were living in her home in Palm Springs, California.

Lommen was arrested on New Year's Day on suspicion of drunk driving and eluding police following a 50-mile (80-kilometer) chase on Interstate 90 in South Dakota that reached speeds surpassing 100 mph. Authorities said they found his mother's body wrapped in a blanket in the back of his sport utility vehicle, and that an autopsy concluded Walsh had died from head and neck injuries.

He was charged with murder in California's Riverside County on Jan. 8.

Lommen had been scheduled to enter pleas Wednesday to South Dakota state charges of felony aggravated eluding and misdemeanor drunken driving, reckless driving and resisting arrest. Assistant Attorney General Scott Roetzel dropped those charges early in the week, and the hearing was canceled.

"We dismissed our file so (Lommen) could go back to (California)," attorney general spokeswoman Sara Rabern said. "The much more serious charges he is facing (are) out west."

Lommen remains jailed in Rapid City in lieu of $2.5 million bond. It wasn't immediately clear when Lommen might be returned to California.