SANDPOINT — A Washington state man who pleaded guilty to a vicious stabbing attack that killed a cab driver in Bonner County is appealing his judgment and conviction to the Idaho Supreme Court.

Appellate counsel for Jacob Corban Coleman contends Judge Barbara Buchanan abused the court’s discretion by imposing an excessive sentence, 1st District Court records show. Coleman, a 21-year-old from Puyallup, was sentenced in January to life in prison with a chance at parole after serving 40 years.

Coleman was charged with first-degree murder in connection with the stabbing death of Gagandeep Singh, whom Coleman hailed a ride from at the Spokane International Airport on Aug. 27, 2017. Coleman directed Singh to drive him to Bonner County, but had the man stop at the Ponderay Walmart, where Coleman purchased a hunting knife that authorities say was used to kill Singh after he stopped his minivan taxicab in Kootenai.

During the ride, Coleman had expressed a desire to kill himself, although sheriff’s investigators said Coleman admitted to concocting a plan to murder Singh not long after entering the man’s cab.

In light of Coleman’s suicidal remarks, Singh unsuccessfully attempted to obtain Coleman’s phone to alert Coleman’s parents, which may have sent him into a rage, according to R. Keith Roark, Coleman’s defense counsel.

Coleman allegedly attacked Singh from the cab’s back seat and dragged him to the van’s passenger compartment, where he was stabbed repeatedly.

Phillip Hanger, a Hayden psychologist who performed court-ordered mental health evaluations of Coleman, testified at sentencing that Coleman suffered from pervasive maladaptive and schizoid personality disorders. However, Coleman’s personality was asocial rather than antisocial or psychotic, Hanger told the court.

Bonner County Prosecutor Louis Marshall recommended a 40-year fixed term due to the cruelty displayed during the attack.

Buchanan adopted the state’s recommendation in the interest of protecting society. The court also reviewed surveillance camera footage from inside the cab in the run-up to Coleman’s sentencing hearing.

“I don’t think I’ve seen anything as disturbing as that video,” Buchanan said during the hearing. “You just sat there playing with your cellphone and watched him die.”

Coleman is serving his sentence at the Idaho State Correctional Institution in Kuna, according to the Idaho Department of Correction. He becomes eligible for parole in 2057, IDOC’s website states.

Keith Kinnaird can be reached by email at kkinnaird@bonnercountydailybee.com and follow him on Twitter @KeithDailyBee.