A 54-year-old Hilo man is set to face sentencing after pleading “no contest” to charges stemming from the sexual assault and kidnapping of a minor. Prosecuting Attorney Kelden Waltjen announced that Duncan Mahi entered the plea in Kona Circuit Court on December 31, 2024.
The charges relate to incidents that occurred on September 16, 2022. Mahi pleaded “no contest” to Sexual Assault in the First Degree, a class A felony, and two counts of Kidnapping, one classified as a class A felony and the other as a class B felony. He remains in custody without bail and is scheduled for sentencing on March 14, 2025.
Under the terms of the plea, Mahi faces a total of 30 years in prison, including a mandatory minimum sentence of 20 years. His sentence includes concurrent terms for the class A felony counts of Sexual Assault in the First Degree and Kidnapping, as well as a consecutive term for the class B felony Kidnapping charge.
Sexual Assault in the First Degree carries a maximum penalty of 20 years in prison, while Kidnapping can result in up to 20 years for class A felony cases and 10 years for class B felony cases, depending on the circumstances.
The case was investigated by the South Kohala Patrol, with the felony investigation led by Detective Steven Grace of the Area II Criminal Investigation Section. Additional support came from members of the Hawai‘i Police Department’s Area I and Area II Criminal Investigation Divisions. Deputy Prosecuting Attorneys Kate Perazich and Kaua Jackson are handling the prosecution.
In a statement, Prosecuting Attorney Waltjen emphasized the significance of victim input in resolving the case. “Sexual assault cases, especially those involving minors, are some of the most traumatic types of criminal victimization.” Waltjen said. “The victims and their families were consulted and very involved throughout the plea negotiations in this case. They confirmed their support of this agreement and resolution of the case.”
Mahi’s sentencing hearing will determine the final terms of his imprisonment.
