A Big Island teenager accused of holding a woman against her will and beating and raping her was sentenced to 20 years in prison.

Tyron Sigrah was sentenced today after pleading guilty to charges of sexual assault, assault, kidnapping and robbery.

Authorities say the 17-year-old and another teen kidnapped the woman and took turns assaulting her at the Old Kona Airport Park in September 2016. The attack stopped after a bystander chased the teens off.

Deputy Public Defender Wendy DeWeese requested for Sigrah, who was 15 when the attack occurred, to receive youthful offender status, which would allow for a prison term of eight years. She told that court that it was “going to send a child to prison.”

The Hawaii Paroling Authority will determine Sigrah’s minimum prison sentence.