The 17-year-old watched the two women from the window of the home where he lived under 24/7 supervision.
One was pregnant. Her 58-year-old mother had come to Canada from Colombia to celebrate her daughter's impending delivery. She saw the boy staring: she said it gave her "the creeps."
The teen would later describe what went through his mind as he watched before he evaded the minders — who thought he was asleep — broke into the house, slipped into the older woman's bedroom and sexually assaulted her.
"I wasn't right in my head," he told the author of a pre-sentencing report. "My thoughts were so focused on the ladies I saw on [sic] the window and I just kept thinking about them."
"I could not control my urges anymore so I decided to sneak into their house."
'Potentially vulnerable females'
Last month, a Vancouver provincial court judge ruled that the young man — who is now 18 — will be sentenced as an adult. He can't be named because of a ban on publication.
According to the decision, his behaviour has already perplexed the youth court system, hospitalized correctional officers and terrorized women in Vancouver where he was arrested in 2016 after random attacks.
"I find the (teen)'s mental health issues and his risk to re-offend require long term treatment, management and supervision," wrote Judge Gregory Rideout.
"His needs will have to be addressed over many years, perhaps for his entire lifetime, to protect potentially vulnerable females from his sexual 'hunger'."
Rideout convicted the teen last summer in a trial that relied on circumstantial evidence and a lone fingerprint left on the window frame of the woman's bedroom when her attacker jumped out of the house to escape.
'A heavy presence'
The woman described being woken in the middle of the night on Sept. 14, 2016 by "a heavy presence in her bedroom."
"She opened her eyes and saw a young man. She tried to see his face but he had something covering his face, though it was not a mask," Rideout wrote.
"She could see his stomach. He had white skin. He was wearing dark small underwear, not boxers. He was shining a small flashlight into her face and he then began to masturbate."
The woman was terrified. She could hear the voices of family arriving home. The teen "began to sniff up and down her body ... at the same time he tried to push down her pyjama bottoms."
As he moved around to her feet, the victim seized the opportunity to flee.
"She ran into her daughter's bedroom screaming that there was a man in her room," Rideout wrote. "Her screams awakened all of the other occupants staying on the upper level."
'His talks weren't working'
The teen was living under the eye of two caregivers hired under the terms of a custody and supervision order that followed nearly two years of constant run-ins with the law.
One testified that he checked on him at 12:30 a.m. and again at 3 a.m. Security camera footage caught the image of figure moving in the adjacent alleyway during the time in between.
The teen was first arrested for assaulting his younger sister in 2015.
He was living at a Vancouver halfway house when he was arrested in March 2016 for random sexual assaults which made headlines when two women reported being grabbed from behind while walking their dogs.
Correctional staff made a decision to limit female staff and volunteers working with the teen because of an "unusually large number" of incidents of inappropriate sexual behaviour.
And in November 2017, two correctional officers were taken to hospital after he started punching them when he was ordered to his room.
The teen discontinued therapy with a psychologist in 2016.
"His talks weren't working," he told the author of the pre-sentence report. "They weren't helping with my sexual urges ... this guy was so boring and he would always talk so long."
'She is afraid of being alone'
The decision to sentence the teen as an adult followed a two-part test to determine his moral culpability and society's need to hold him accountable with a longer sentence. Rideout was also required to consider his First Nations status.
In her victim impact statement, the woman described feeling feelings of paranoia.
"She is afraid of being alone. She suffers from panic attacks at night and finds it difficult to fall sleep. She experiences headaches and fatigue," Rideout wrote.
"She is worried that in the future the (teen) will take revenge against her family, which frightens her."
It later emerged that the teen had also broken into the house the night before committing the assault.
"I have taken into account my finding that the (teen) planned and premeditated the index offences over a period of time," Rideout wrote.
"He knew what he was doing and he knew it was wrong. His commission of the index offences was neither an impulsive act, nor an act explained by immaturity."
The Crown is asking for a sentence of four years.