Officers found human remains, a walking stick with her name on it and a pile of her clothes at an inlet connected to a creek infested with large saltwater crocodiles.
"Because of the proximity of these items and this unknown material located near this creek bank, we can not rule out the possibility of a croc attack", Acting Inspector Ed Lukin told reporters at a news conference.
"We've also located some biological matter which we believe to be human remains, but those items are now being tested in Cairns", acting inspector Ed Lukin said, according to ABC.
The family of Anne Cameron took to Facebook to say they "firmly" believed she had passed away in "tragic circumstances".
Anne Cameron, 79, went missing from an aged care home in Port Douglas, north of Cairns, on Tuesday afternoon.
Results are expected today from forensic testing on "biological matter" found near clothing and a walking stick after Ms Cameron, a dementia sufferer, went missing from her nursing home.
Authorities were on Friday hunting a crocodile suspected to have snatched an elderly woman at a creek in northern Australia, police said.
"We still hold out hope that we will find this missing person alive".
Lukin said police believed Cameron had wandered into the dense bushland, where she became lost, but it was not known if she had entered the water.
State Emergency Service area controller Sean McGuinness said the search is proving to be hard.
Fellow resident Judith Wright said she saw Ms Cameron walking towards the facility's administration building shortly before 4:00 on Tuesday, the day she disappeared.
A former neighbour of Mrs Cameron said she had moved to Port Douglas from Canberra, where she had lived most of her life, within the past year in order to be closer to her family.
State rangers set crocodile traps on Thursday night, he said.

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