A Logan woman who killed her deceased twin sister's baby three months after becoming the child's carer has been jailed for nine years.
WARNING: This report contains content some people may find distressing.
Five-month-old Senah Houston was taken to hospital in November 2018 by her aunt Sandra Leigh Houston in a critical condition and died the next day.
After voluntarily making admissions to police, Houston, 38, was charged a month later with her niece's murder.
On Wednesday, Houston pleaded guilty to the lesser charge of manslaughter in the Supreme Court in Brisbane, with the prosecution accepting she did not intend to cause the baby's death.
She also admitted to one count each of grievous bodily harm and child cruelty.
During a sentencing hearing, the court heard Houston had only been caring for Senah for three months, after the child's mother – her twin sister – died suddenly in August 2018.
The court heard on the day before Senah died, Houston's husband Jason Bowman found her "limp, cold and floppy" in a bedroom at their Waterford West home and he and Houston drove her to the Logan Hospital.
Crown Prosecutor Mark Green told the court when they arrived, Senah was "deeply comatose" but Houston "showed no urgency" when she entered the emergency room with her.
Couple did not check on baby in hospital
The court heard while the baby was being treated, which included being flown to another hospital, and up until her life support was turned off, neither Houston or Mr Bowman returned to be with her or enquired about her condition.
Mr Green told the court Senah had suffered "traumatic" head injuries which were consistent with being shaken and put down forcibly, and had almost 40 other injuries including bruises, abrasions, and fractures to several bones.
"Some of the injuries show healing … which suggest they were inflicted at different times," he said.
At the time Houston told police "it is possible I exerted too much force on the baby" but later told a psychologist she was regularly "irritated" with her and would smack her forcefully, and on the day before her death had thrown her from between "waist and chest height".
Mr Green told the court the psychologist report revealed Houston had admitted to "roughly" dealing with Senah on multiple occasions, but she "felt nothing" after doing so, because she did not believe it was wrong.
"It was in fact a pattern of behaviour and is not an isolated incident," he said.
The court heard Houston had been diagnosed with an adjustment disorder with "with mixed disturbance or emotions and conduct" but this did not cause her to "act out of character" though it may explain the escalation in offending.
Houston's sister was her 'only friend'
Houston's defence lawyer Catherine Morgan told the court her client "unravelled" after the death of her sister who was her "only friend", and it was "hardly surprising" she could not handle the responsibility.
"It is easy to be critical of the parenting of a mother who found herself in that situation," she said.
Ms Morgan told the court Houston was "not a woman without conscience" and was "genuinely remorseful".
"She has lost her home, she has lost her family … she has been punished significantly."
Justice Thomas Bradley told the court "cruelty was an apt description" for her offending against a "very young and vulnerable child" who should have been protected.
"One of the few means left to show care for Senah is to impose a just and appropriate sentence for your conduct, which ended her life and before then, involved cruel and ultimately lethal mistreatment of her," he said.
When determining his sentence, Justice Bradley took into consideration Houston's lack of a criminal history, her bereavement, and accepted a letter she wrote to the court last week, which stated she felt "ashamed and deeply guilty".
He also declared her a serious violent offender meaning she will have to serve at least 80 per cent of her sentence.
