She was a 55-year-old patient in a nursing home who had difficulty moving or speaking and had to use adult diapers.
But the multiple-stroke victim was molested by a 34-year-old man who worked in the home.
Yesterday, after a 14-day trial, the man was sentenced to 22 months in jail and three strokes of the cane on one count of outraging a woman's modesty.
The victim - now 57 - the man, the nursing home and the sole eyewitness in the case cannot be named due to a gag order.
The court heard that on the day of the incident - Nov 26, 2016 - a nurse was going about her rounds when she noticed that curtains around many of the beds were drawn in the victim's room.
She found that unusual as the curtains were typically drawn only when diapers were being changed.
When she went into the room to check on a patient, she heard cries from the victim.
She turned and saw the man straddling the victim, who was lying in bed on her back.
The nurse testified that she could see the man's trousers had been pulled down to thigh level and that the victim's pants were also lowered.
The left side of her diaper was removed and the man's groin was touching the victim.
The man did not realise that the nurse was in the room but she could see part of his face and recognised him as a housekeeping employee.
She later reported the incident to the management of the home, who eventually alerted the police.
The victim, a Singaporean, had been a resident in the home for more than five years when the incident took place. She did not testify as she was assessed to be medically unfit to do so.
She was also found to be incapable of giving legal consent to any sexual act due to her mental incapacity.
But the court heard that during an interview with a psychiatrist, she showed signs of distress, breaking down several times as she recounted in simple Malay that a man had come to her bed and that she was touched and her pants were pulled down even though she objected.
Deputy Public Prosecutor (DPP) N. K. Anitha said that it was "sheer fortuity" that the man was caught in the "callous" act of targeting a vulnerable and defenceless victim.
She described the act as "premeditated", noting how the victim's bed was tucked in the innermost corner of the room.
On the day of the incident, there was a community involvement programme on the first level of the home and usually, the victim as well as other bed-bound or asocial residents would not have taken part in such events.
The man, who is married with a daughter, denied the charge, stating in court that he was in the victim's room to repair another patient's television set. The man, who has been working in the home since 2010, says the nurse who described the act was mistaken since she only took a very quick look and was also tired at the time of the incident having worked for over eight hours in the home, which was understaffed.
He is planning to appeal against his conviction and sentence.
For outraging a woman's modesty, he could have been sentenced to up to two years, with a fine or caning or both.