Jaylen Troy Priest, aged 16 months, suffered a fractured skull and brain bleed at his home at Burpengary, north of Brisbane, on December 30, 2021.
He died in hospital more than a week later.
Aaron Harley James, the partner of the boy's mother, Savannah-Rose Wilson, spent more than two years in custody accused of killing his stepson.
Mr James was freed in 2024 when prosecutors dropped charges against him.
Queensland Police on Friday said ongoing investigations had "identified a number of inconsistencies from information initially provided".Â
Investigators renewed their appeal, first launched after the toddler's death in 2022, for anyone who witnessed suspicious activity or concerning behaviour towards a boy in the area near Staaten Street before December 30, 2021 to contact authorities.
After the charges against Mr James were dropped, Justice Peter Callaghan said the tragedy "would not be compounded by the conviction of an innocent man".
It emerged that a 14-year-old child had been pressed for information in a police interview before giving a second statement relating to the case.
There was no evidence of violence or mistreatment by Mr James against the child, Justice Callaghan said at the time.
It was a wet day, there was water on a hard floor and the boy slipped while running, the judge said the evidence of witnesses suggested.
He hit his head, suffering a fractured skull and brain bleed, the court was told.
Ms Wilson, who has her son's name tattooed on her shoulder, said she had not been able to grieve for her "beautiful" son until the case was resolved.
"My son can rest finally," she said after the charges were dropped.
"I've lost family, I've lost friends because we've been painted as murderers and we loved our son."
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