Police investigating the disappearance of Melbourne teenager Siriyakorn "Bung" Siriboon say they will consider offering a reward so they can finally give her family some answers.
Clothing and animal bones have been found in a Boronia reserve that police began searching on Monday, but as yet officers have found nothing of any value to the investigation.
They say their search of the Old Joes Creek Retarding Basin will continue until they are satisfied there is nothing to be found.
Bung, then aged 13, vanished after leaving her house in Elsie Street, Boronia, in June 2011 on her way to school.
Homicide Squad Detective Inspector John Potter said a reward was being considered by police.
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"If we think a reward can help in an investigation then we would certainly pursue that," he told reporters at the scene on Tuesday.
Det Insp Potter said Bung's family is being kept updated on the search.
"We are hoping that ultimately we will find something and provide answers to the family, but at this stage we've found nothing," he said.
"At this stage they are still holding out hope that Bung is alive."
Det Insp Potter said police are searching the area after receiving new information.
"We are not convinced it's particularly credible, the information, but we need to search this area for completeness sake," he said.
"This forms part of our strategy to continue to leave no stone unturned in our search for Bung."
The retarding basin, approximately 3km from Bung's home, sits in a rugged, heavily-treed area.
A creek runs through the middle of the area, which also contains a track popular with dog walkers.
Houses back onto the 2.2-hectare area which has been fenced off as the search, involving police, SES personnel and two cadaver dogs from Queensland, takes place.
Bung left her home around 8.30am on Thursday June 2, 2011.
She was seen by a neighbour a short time later in Elsie Street, walking towards Albert Avenue.
Bung did not arrive at school that day and has not been seen or heard from since.
Police say they have received 900 Crime Stoppers calls about Bung's disappearance.
