GREEK police want to use specialist 3D scanners to try to discover if missing Sheffield boy Ben Needham is buried at a building.
Investigators want to search the land around the farmhouse from where he vanished 21 years ago.
But Ben’s mum Kerry Grist, 40, of Ecclesfield, said she is unconvinced about the new theory - although she said is pleased the Greek authorities are taking her son’s disappearance seriously.
She said she refuses to believe her son is dead and still thinks he was snatched by Gypsies.
Greek police have asked for specialist equipment from Britain to be sent to the holiday isle of Kos, where Ben disappeared in 1991, to help them investigate a new theory that Ben may have been buried by accident near to the farmhouse his grandfather was renovating.
Detectives have discovered that on the day Ben vanished earth was being piled near to the farmhouse from a site where a new house was to be built.
JCB driver Konstantinos Barkas has given a statement to police in Greece confirming he was excavating earth the day Ben disappeared and has suggested the youngster may have been buried rather than abducted.
Greek authorities have informed South Yorkshire Police of their latest theory.
South Yorkshire Police said officers were ‘undertaking a review’ of the latest theory.
A spokesman said: “The investigation into the disappearance of Ben Needham remains with the Greek authorities.
“Should they request any help or support from South Yorkshire Police we will look to support them where we can and within our resources. The force’s role is primarily to provide ongoing support to Ben’s family, in particular his mum Kerry.
Colonel Sentonas St Stergos, of Kos Police, said: “More than anything we want to help bring this nightmare to an end for Ben’s parents.
“They have to know what happened to him.”
n July 1991: Ben Needham, aged two, disappears on Greek island of Kos.
n October 2007: computerised image is produced to show how Ben could look aged 18.
n September 2011: Greek authorities re-open case into disappearance.
n September 2011: Ben’s mum meets British Government officials for the first time since her son Ben vanished.
n December 2011: Ben’s family win permission to obtain his DNA from hospital where he was born, to check against databases around the world.