DENVER—Jurors deadlocked and a mistrial was declared on Thursday in the kidnapping-murder case against a two-time Idaho gubernatorial candidate charged in the 1984 slaying of a 12-year-old Colorado girl whose remains were unearthed over three decades later. The 12-member jury found Steven Pankey, 70, guilty on one count of false reporting to authorities but failed to reach a unanimous verdict on charges he abducted and murdered Jonelle Matthews, leading the judge to dismiss most of the prosecution’s case, court officials said. Weld County Judge Timothy Kerns set a status hearing for next Monday to address the potential re-filing of kidnapping and murder charges, in addition to bond and sentencing on the false reporting count. The hung jury, which began its deliberations at midday on Tuesday, capped a three-week trial stemming from Matthews’ death. The girl vanished in December 1984 from her Greeley, Colorado, home, about 50 miles north of Denver, …