Tasmanian man Daniel Ridger's loving posts to his fiancée before he allegedly murdered her 10-month-old boy

A 25-year-old man accused of killing a 10-month-old baby is engaged to the little boy's mother, it can be revealed.

Daniel John Ridgers allegedly violently shook Khaylan Shane Butler and then dropped him into his cot at a home in Warrane, in Tasmania's south, late on Thursday night. 

Khaylan was rushed to hospital with critical injuries during the early hours of Friday morning, but tragically died several days later. 

Ridgers is the fiancé of Khylan's mother, Maddison Butler, and has his own children from a previous relationship. 

Ridgers frequently shared gushing posts online paying tribute to his 'beautiful' partner.  

'Happiest birthday ti [sic] my wife to be,' he wrote on November 17, just two weeks before the alleged attack. 

Ms Butler responded: 'Thanks baby. I love you.'

In another post earlier that month, Ridgers wrote: 'I love you beautiful, can't wait to marry you.' 

Ms Butler also expressed her love for her fiancé on several posts online.

Early last month, when he expressed concerns about how other people perceive him, she commented: 'F*** em all babe, we got this,' she said. 

Khalyan was the youngest of two boys and photos posted online show him being doted upon by his mother and older brother. 

Just four months ago, his mum shared a sweet video showing the baby smiling joyfully as she pushed him in a swing.  

Tasmania Police issued a statement on Monday announcing the little boy had died after presenting to hospital late last week. 

The force offered its condolences to his loved ones and said the police investigation remains ongoing. 

Family friend Brianna Jeanneret said Khaylan had made a big impact on everybody around him during his short life. 

'Never would you have met a happier baby, whose giggles gifted joy to all those he was close to,' she said.

Ms Jeanneret has launched a GoFundMe to help Ms Butler cover the cost of her son's funeral, which has so far raised $5960 of its $12,000 goal. 

Ridgers was arrested on Sunday and charged with assault causing grievous bodily harm.

He faced Hobart Magistrates Court on Monday after his charge was upgraded to a single count of murder in the wake of Khaylan's death. 

He did not enter a plea and he was refused bail to next appear in court on January 5, 2024. 

Anyone with information that may help the investigation is asked to call Bellerive CIB on 131 444 or Crime Stoppers.