SYDNEY (Reuters) - The discovery of fresh footprints in Australia‘s Great Sandy Desert has raised the prospect that a U.S. tourist missing for more than a month may still be alive in the harsh outback, police said on Friday. Police, who had given up searching for Alaskan builder Robert Bogucki, 33, said they now believe he may have been hiding from searchers in an attempt to „test his spirituality“ on an 800 km (500 mile) trek. Barefoot prints, similar to those police and Aboriginal trackers followed earlier in a two-week search, were discovered on Thursday by a local exploration driver. „On two occasions we have picked up barefoot prints, where he appears to take his shoes off at night time and walk barefooted,“ said police sergeant Geoff Fuller in Broome on Australia‘s remote northwest coast. A U.S. search team with bloodhounds, which arrived in Australia on Tuesday, picked up the fresh tracks on Friday. Bogucki attempted to cross Western Australia‘s Great Sandy Desert, which boasts towering 11 metre (36 feet) sand dunes and impenetrable scrub, in July. In a July 13 postcard sent to his parents in Malibu he said he intended to ride his bicycle across the desert. But since his departure, only his abandoned bicycle, camping gear and footprints have been found. Police said Bogucki‘s girlfriend had told them that he may be avoiding search teams to test his survival skills.