Prisoners’ revenge as killer who beat toddler until his insides ruptured then told him ‘shut up’ has skull broken in jail

William Andrew O’Sullivan suffered a fractured skull when he was bashed, kicked,stomped and knocked unconscious by two inmates earlier this year while in custody over the death of 22-month-old Mason Jet Lee. 

Details of the ‘savage assault’ emerge last week as O’Sullivan was jailed for just nine years for the manslaughter of Mason.

His stepdad beat him so severely his small intestine burst – then simply looked on as his organs shut down, his stomach swelled up and his nappies became blood-soaked.

Whenever he cried in pain and vomited, O’Sullivan would shout at him to “shut up”.

The little boy died alone, covered in vomit, on a bedroom floor at his killer’s home in Caboolture, Queensland, Australia.

The child had skin loss in the perianal region – the area around the anus – similar to “that of a burn” that could have been caused by a range of factors, it was said.

Possible causes included a bad diet, a lack of regular nappy changes and a hose that was used by O’Sullivan to clean the little boy.

Mason spent several weeks in hospital at the time. He later returned home, but died months later after his stepfather struck him and perforated his intestine.

However, he later pleaded guilty to  Chief Justice Catherine Holmes on the charges of manslaughter and child cruelty and was sentenced to nine years behind bars on August 30, with a six-year non-parole period.

This means he could be free in under four years, in July 2022.

His ‘lenient’ term has reportedly sparked calls for an urgent appeal.