Members of a police team from South Yorkshire have arrived on Kos before a search for the remains of Ben Needham begins next week.
They are due to start excavating two sites on the Greek island from Monday.
The team is looking for the remains of Ben Needham, from Sheffield, who vanished on Kos in 1991 when he was 21 months old.
He had been playing outside a farmhouse his grandfather was renovating when he went missing.
Police suspect Ben may have been buried by a digger which was clearing a building plot next to the farmhouse.
Material was moved by the digger to two sites on the island, which are to be cordoned off and searched.
The man who was operating the digger died last year but a friend came forward suggesting what may have happened and detectives have told Ben's family to 'prepare for the worst'.
Ben's mum, Kerry Needham, writing on a Facebook page set up to share news about the search for her son, said today: “South Yorkshire Police have my full support during this very painful time. "These officers have worked tirelessly over the last five years.
"It's an honour to have such dedicated officers by my side, helping me get through this."