A 15-year-old boy will remain in youth detention for at least three years after he committed a frightening, violent sexual assault on a female health care worker in Alice Springs last year.

The Northern Territory Supreme Court heard the boy had been drinking alcohol, smoking cannabis and watching pornography before the offence took place on December 13 last year.

The victim was finishing work for the day when the boy knocked on the back door of a health facility at 8.40pm, forcing his way in despite her resistance.

He then forced the victim to perform a sexual act on him during a terrifying 25-minute ordeal.

After the incident concluded, the boy told the victim “not to tell anyone” before he fled.

Justice Jenny Blokland said the offending was “clearly a most aggressive sexual assault”.

“The whole episode must have been terrifying for the victim,” Justice Blokland said.  

“(The boy) used his superior physical strength to overpower the victim both in relation to the unlawful entry and the ensuing brutal sexual assault.

“It was a revolting experience for the victim … it has caused detriment to her mental health, wellbeing, and sense of personal security.”

The court heard the boy suffered from fetal alcohol syndrome and was on a Youth Justice Court-ordered bond at the time of the offending.

His previous offences included unlawful entry of a building with intent, stealing and property damage.

Justice Blokland ordered the boy serve a total of six years detention. Under the powers of the Youth Justice Act, a non-parole period of three years was set.

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