(BIVN) – 54 year-old Duncan Mahi has been sentenced to a 30-year prison term for the sexual assault and kidnapping of two minors in September 2022. 

Prosecutors say Mahi appeared in Kona Circuit Court on December 31, 2024, where he entered “No Contest” pleas to charges of Sexual Assault in the First Degree and two counts of Kidnapping. 

Mahi abducted of a 15-year-old from Anaehoʻomalu Bay in Waikoloa on September 16, 2022,  law enforcement officials reported. The event triggered a MAILE AMBER Alert and prompted a large search effort. The next day in Hilo, the survivor was able to free herself from her captor with the assistance of several good Samaritans. She reportedly convinced Mahi to stop for food at Cafe Pesto, at which time she was able to make her escape. Mahi was located and arrested later that day.

FILE PHOTO: A police car sits outside the area of Downtown Hilo where the victim was found on September 17, 2022.

Mahi was held without bail, and remained in custody throughout the duration of the court proceedings. 

From the office of the Hawaiʻi County Prosecuting Attorney, Kelden Waltjen:

Mahi pleaded “No Contest” to Kidnapping (class A felony) with a mandatory minimum of thirteen years and four months in Count 1, Kidnapping (class B felony) with a mandatory minimum of six years and eight months in Count 2, and Sexual Assault in the First Degree (class A felony) with a mandatory minimum of thirteen years and four months in Count 8. Counts 1 and 8 will be served concurrently to each other and consecutive to Count 2 for a combined total of thirty years with a twenty-year mandatory minimum total.

Sexual Assault in the First Degree is a class A felony offense and carries a maximum penalty of a twenty-year prison term. Kidnapping can be a class A or B felony offense depending on facts and circumstances. Class B felony offenses carry a maximum penalty of a ten-year prison term.

“Our Office values victim input and the importance of victim well-being,” said Prosecuting Attorney Kelden Waltjen in a written statement. “Sexual assault cases, especially those involving minors, are some of the most traumatic types of criminal victimization. The victims and their families were consulted and very involved throughout the plea negotiations in this case.” 

“I would like to recognize the hard work and dedication of Deputy Prosecuting Attorneys Kate Perazich and Kaua Jackson, our Office’s Victim’s Assistance Unit, the Hawai‘i Police Department, lead detective Steven Grace, and all the other officers and personnel who worked on this case, as well as our federal and state law enforcement partners,” Waltjen added. 

“Mahalo to Missing Child Center and Statewide MAILE AMBER Alert Coordinator Amanda Leonard,” Waltjen noted. “I’d also like to recognize Bridge Hartman and Kori Takaki whose quick thinking and actions likely saved her life. And last but certainly not least, I’d like to recognize the bravery and courage of our survivors. I hope today’s sentencing offers them and their families some closure and a sense that justice was served.” 

“Hawai‘i Island is a Big Island but a small community,” Waltjen concluded. “We come together, we lean on each other for strength, and that’s what makes us resilient. The survivors and their ‘ohana know . . . that Hawai‘i Island will always be here for them.” 

The investigation was initiated by South Kohala Patrol, and the felony investigation was led by Detective Steven Grace, Area II Criminal Investigation Section, and assisted by members of the Area I Criminal Investigation Division and Area II Criminal Investigation Division, Hawai‘i Police Department. The case was prosecuted by Deputy Prosecuting Attorneys Kate Perazich and Kaua Jackson.