Australian police searching for a missing four-year-old girl are saying they will "leave no stone unturned" as they urged members of the public to come forward.Cleo Smith was last seen in her family's tent at about 1.30am local time on Saturday (October 16), at a remote campsite in Macleod, more than 500 miles north of Perth.Police say that when her parents woke at 6.30am she was gone.An extensive search began at the weekend and additional forensic staff arrived from Perth on Monday (October 18), alongside police, defence force and community members already scouring the rugged area."We are not going to get blinkered or sort of assume that something has happened. Everything is on the table, until we can actually rule it out. At this point in time, unfortunately, everything is still on the table."Police also released a picture of a sleeping bag that was also missing from the site.Local media reported that the family had been visiting for a weekend camping trip but were now staying in the area.