The man who killed Caboolture toddler Mason Jet Lee has had his sentence increased to 12 years after a court of appeal quashed the original nine-year sentence.

William Andrew O’Sullivan pleaded guilty to manslaughter after his 22-month-old stepson died from sepsis caused when his bowel was pierced by some kind of blunt force.

The court had heard the toddler suffered for days before dying, with abdominal pain, fevers and vomiting.

After Mason died, traces of methamphetamine were found in his blood.

The 37-year-old admitted he beat the boy days before his death and the judge believed the self-described ‘junkie’ was under the influence of meth at the time.

Nine News reporter Shannon Marshall-McCormack tells Mark Levy the toddler’s mother’s sentence of nine years has been upheld.

“They say it is adequate given that she was unable to intervene, despite being the mother, given the violent and fractured nature of her relationship with O’Sullivan.

“It was a case that absolutely sickened people. ”

Click PLAY below to hear the full interview

Image: Facebook/Emmy Louise