Fresh searches of a remote bush track area in southern Tasmania are being conducted as police probe the disappearance of a 66-year-old man six years ago.
Avid bushwalker Bruce Fairfax was reported missing from the Duckhole Lake track area in October 2017, with extensive searches finding no trace of him.
Tasmania Police in late October revealed the disappearance of the former teacher was being treated as a criminal matter.
Police and search and rescue personnel started combing the track area on Thursday and will continue on Friday.
Mr Fairfax was reported missing after he and his wife became separated while the couple was on a walk with their dog.
Police in October said "fresh eyes" on the matter sparked the criminal investigation.
Witnesses have been re-interviewed and police have indicated they are keeping an open mind to all possibilities, including that Mr Fairfax was never at the lake.
About 60 people, including Mr Fairfax's daughters and former students, were involved in the initial lake area search which was called off after about a week.
Duckhole Lake in Tasmania's Southwest National Park is a flooded sinkhole, part of an extensive regional cave system.
Mr Fairfax, who required daily medication for Parkinson's disease, was described by his wife as a "gentle, patient, generous giant".
Police have urged anyone with information to come forward.
