It’s been more than half a century since Joanne Ratcliffe and Kirste Gordon vanished, and every year that passes brings more questions.

Joanne was 11 and Kirste only four when they disappeared from Adelaide Oval in 1973, almost certainly abducted and murdered.

“Families of long-term missing persons, we can’t move on, we’re living a life of limbo, not knowing what happened to our love ones,” Joanne’s sister, Suzie Ratcliffe, told 9News.

Now, 9News can reveal a renewed search for answers.

“I’m adamant this is going to solve the case, if it doesn’t at least it’s checked out,” South Australian journalist Bryan Littlely said.

A team of private investigators will explore two key mid-north sites between Jamestown and Orroroo.

First, they’ll dig at a farm just north of the small community of Yatina, before revisiting a tunnel at the nearby Pekina Reservoir.

The locations have been pinpointed in handwritten claims by convicted paedophile Mark Trevor Marshall, who accused his own grandfather, Stanley Arthur Hart, of abducting the little girls.

While Hart’s mid-north farmhouse was previously searched by police, this new private effort focuses on sites nearby.

“The statement that Mark Marshall made, put an X on the map on that exact spot, and said this is where the two girls were buried and disposed of in barrels,” Littlely said.

In 2009, the private investigation team did find barrels in the tunnel, but they contained no trace of the girls. This weekend’s search will go further.

“If it’s thoroughly excavated and thoroughly searched, then we can rule that out,” Ratcliffe said.

Last month there was a privately run dig at North Plympton relating to the disappearance of the Beaumont children in 1966. Nothing was found; now, new hope, albeit faint, comes to the equally tragic Ratcliffe-Gordon case.

”I’m tired of being quiet, I’m tired of waiting, I’m tired of just being tired, I want the girls home,” Ratcliffe said.