Police remain hopeful they will find missing 11-year-old Luke Shambrook who went missing from a campsite in Victoria on Friday . An increased number of police and other emergency crews continue to scour the thick bushland areas around Lake Eildon in an effort to find the boy . Search co-ordinator Acting Senior Sergeant Andrew Walker said Luke had a “ very high pain tolerance ” , a factor that would work in his favour given he has now been missing for days . Scroll down for video . The Shambrook family with children ( left to right ) Luke , 11 , Lauren , 7 , and Matthew , 10 . Luke Shambrook was last seen on the national park at 9.30am on Good Friday . It is understood he wandered off and has not been seen since . “ Hence the reason why we ’ re out searching . We ’ re still hopeful that we can find him , ” Sgt Walker said . The 11-year-old , who is autistic , was reportedly seen walking near the Devils River on Sunday , four kilometres south of his campsite where he was last seen . Search crews have rushed to the location and police remain comfortable that the young boy is still alive . Luke has now been missing for four days . A Victorian Police spokeswoman told AAP late on Sunday that a family saw a young boy matching Lukes description while they were driving in the Devils River vicinity . With temperatures dropping to as low as eight degree Celsius , Senior Sergeant Ralph Willingham believes that the fourth day of searching will have a further level of urgency . 'The advice I 'm getting from our search and rescue experts having regard to the overnight temperatures and the daytime temperatures is that he could well still be out there , ' he said . 'We 've got to be realists but we 're positive , the family 's positive . ' However , Luke may not even know he is lost and is known to frequently hide , according to his family . He was last seen leaving Candlebark Campground in Fraser National Park near Lake Eildon at 9.30am on Good Friday . Luke has limited speech and his family says he is probably confused , and he may not even be aware he is lost . Campers are helping rescue teams including the air wing , dog squad , local police and SES volunteers in the search of thick bushland . Police hold hope that Luke has been able to stay reasonably warm as he was last seen wearing a beanie and warm jacket . There was a moment of hope when a beanie was found by the search party , however it was decided it did not belong to Luke . The Candlebark Campground in Fraser National Park , central Victoria , where Luke went missing on Friday . Having met Luke 's family during a push to open a special school in Melbourne 's southeast , Opposition emergency services spokeman Brad Battin says it 's devastating to hear the 11-year-old is missing . He says Luke 's parents Tim and Rachel have been updating him on the search and appreciate the efforts of all those out looking for their little boy . 'He 's a lovely young kid , ' Mr Battin told AAP on Sunday . 'He displays all the characteristics of a child with autism , which means he might not even think he is lost . ' Sergeant Greg Paul says the search is focused on an area of several kilometres of bushland . 'We 've got a lot of searchers in the bush , we 've got a lot searchers searching all the tracks and in between the tracks and the gullies and the spurs , ' he told reporters on Saturday . The Shambrook family has thanked emergency service workers , volunteers , family and friends for their help . They say the disappearance is completely out of character for him . A widespread search is being carried by search and rescue teams including the air wing , dog squad , local police and SES members , along with campers around the surrounding areas . A large search is being carried by a medley of search and rescue teams . Sergeant Greg Paul said the search was focused on an area of several kilometres of bushland . 'We 've got a lot of searchers in the bush , ' he told reporters on Saturday . 'We 've also got people walking the banks of the lake . ' But he outlined a serious hurdle for the search efforts , according to ABC . 'With the autistic condition , Luke might not respond to searchers , he may not even know that he 's lost , ' he said . 'He wo n't necessarily respond to his name being called , but that might change a little bit as he gets hungry maybe . Sgt Paul said there were hundreds of other campers in the area over the busy Easter period , so there was a chance someone else could spot Luke . Luke is described as being of medium build , about 150 cm tall with olive skin , brown hair and brown eyes . He was last seen wearing a black windcheater , black t-shirt , grey track-pants , grey boots and a scarf . Lake Eildon , near where Luke went missing : Police say conditions are favourable for his survival overnight , with warm temperatures through the day . Sergeant Greg Paul said the search was focused on an area of several kilometres of bushland . Searchers are desperately combing bushland and the banks of a lake for an autistic who went missing there . A widespread search is being carried by search and rescue teams including the dog squad and local police .
Luke Shambrook was last seen leaving Candlebark Campground on Friday . There has been an unconfirmed sighting of Luke with police acting quickly . The 11-year-old was reportedly seen walking 4 kms from his campsite . Police remain hopeful they will find Luke , who has 'high pain tolerance ' Luke has limited speech and his family says he is probably confused . A large search is being carried by a medley of search and rescue teams . A man in the US state of Washington has died after falling off a cliff while trying to take part in a water skiing event. They have issued an extensive description of Luke and his clothing .