The man convicted of assaulting and kidnapping a 95-year-old woman in Casper last year before leading police on a high-speed chase should continue serving a lengthy prison sentence handed down in December, the Wyoming Supreme Court ruled Wednesday.

Kyle McCabe Martin, 21, was sentenced to a prison term of 75 years to life for aggravated kidnapping. During the Dec. 6 sentencing hearing, District Judge Catherine Wilking also sentenced Martin to concurrent terms of 20-25 years each for aggravated robbery and aggravated assault.

On Dec. 19, Martin appealed the sentence to the Wyoming Supreme Court. Then, on April 3, Martin's court-appointed attorney filed a motion to withdraw from the case.

The following day, according to the ruling from the high court, Martin was given additional time to file a brief. That brief, which was supposed to specify the issues Martin would like the court to consider in his appeal, had a deadline of May 20.

The court at that time also said it would, after that filing period expired, rule on the attorney's motion to withdraw and then make a final decision on the appeal.

Martin did not file his brief or any other pleading by May 20, the court said. On Wednesday, the high court affirmed Wilking's judgment and sentence, and allowed the Wyoming Public Defender's Office to withdraw as counsel for Martin.

Martin could still appeal the sentence in federal court.