This week the 46-year-old drove from her home in Auckland to Tokoroa to meet Jefferie's mother, Jo Reynolds, and to lay a rose in the creek in memory of her playmate.
"I feel sad that she's got no closure, that's why I went there."
An extensive search of the creek by 400 police and volunteers in the days after Jefferie's disappearance failed to find his body.
In March 1969 a coroner ruled Jefferie had drowned in the creek, but last week police excavated an area of the Stubbs' old property, across the road from the Hills' former house, after a geophysics scientist detected an anomaly in the ground which police believed could have been Jefferie's remains. The anomaly turned out to be a tomo, or underground hole.
Mrs Booker remains convinced the little boy slipped into the creek which flows to the Waikato River.
"All I know is that we were at that creek and he went in that water. We were both there and we shouldn't have been - we were only little."
Mrs Booker's mother, Colleen Ward, who raised the alarm when her daughter ran back from the creek that day, said her daughter was telling the truth.
"She said 'Mum, Mum, Jefferie's gone in the creek', and she was crying.
"He was trying to retrieve Karen's red shoe because she had taken her shoe off. The creek was swollen because we'd had a lot of heavy rain prior to the disappearance."
Mrs Ward, then Mrs Stubbs, said the youngsters had been playing in the Stubbs' sandpit before wandering off to the stream. She was inside feeding her five-month-old son while her husband, Tom, was fixing the baby's bassinet.
After the incident Mrs Booker was blamed for Jefferie's disappearance by other children who taunted her, saying she had pushed him in the creek.
"I would come in crying saying 'they said I killed him'. That tormented me, I was quite an insecure girl."
Mrs Booker said her father, Tom Stubbs, was "a very loving dad. I'm a bit hurt about what they said about Dad."
Mr Stubbs, who died after a heart attack in 1987, was reportedly aggressive toward the neighbourhood children, and one former neighbour said he saw Mr Stubbs digging at the property two days after Jefferie disappeared. She said if her father was grumpy toward other children it was because they were picking on her, and because he was much older.
When the Stubbs' marriage ended the family moved away to start afresh.
Mrs Ward said her former husband did not have a criminal record, had served in World War II and was a hardworking insurance salesman.
"He wasn't a black devil as everybody seems to be seeing him as. They've picked on Tom, they've blackened his name."
A psychologist, asked about Mrs Booker's childhood memories, said children's earliest memories began when their verbal skills developed.
University of Waikato School of Psychology senior lecturer Dr Carrie Barber said children aged 30 months "do have some memory for the sequence of things, for what happened. But they can't necessarily report it clearly."
Mrs Reynolds and her daughter, Laura Hill, told the Herald during the excavation they thought Jefferie might still be alive, unaware of his past life.
The pair believed there was every possibility that Jefferie may have been abducted and raised by someone else as their own.
