The distraught family of a missing preschooler say they are holding on to hope "he will be found and returned safely" after the boy vanished while playing on a remote sheep property.
Four-year-old August, known as Gus, disappeared from his family's property in the remote South Australian mid-north on Saturday afternoon.
Now in the fourth day of the search, a friend of the boy's family, Bill Harbison, read a statement on their behalf on Tuesday, saying they were "devastated by the disappearance of our beloved Gus".

Police do not believe the four-year-old's disappearance is suspicious. Source: Supplied / Channel Seven
"Gus’s absence is felt in all of us, and we miss him more than words can express.
"Our hearts are aching and we are holding onto hope that he will be found and returned to us safely."
Despite frantic efforts, the boy's family have found no trace of him and called emergency crews to widen the search around their property near Yunta, about 300km north of Adelaide.
Yorke Mid North Police called in PolAir and infra-red cameras, but they have been unable to find the boy.

The extensive search for the missing boy has involved SES volunteers on trailbikes, all-terrain vehicles, dogs and a drone. Source: Supplied / Channel Seven
Aerial searches continued throughout the night and into Tuesday, when ground operations restarted.
'Still very optimistic'
While fears are escalating for the safety of the missing boy, police do not believe his disappearance is suspicious.
"There's no suggestion of that," superintendent Mark Syrus said on Monday.
"The road here, it's not a public thoroughfare. The only people who would travel on this road are station owners or people servicing those areas.
"This poor lad is just four years old and very close to the family."
Searchers continued to cling to hope that Gus will be found alive despite daily maximum temperatures reaching 30C.
"It would be uncomfortable for him ... every moment that ticks away, we are concerned that we haven't found him, but still very optimistic," Syrus said.
Gus has long, blond, curly hair. He was wearing a grey sun hat, a cobalt blue T-shirt with a yellow minion on the front, light grey long pants and boots.