Rosie Johnson, 22, hasn’t been seen since Sunday after she vanished on the Isle of Wight.
The Scottish zoology graduate – who works at the PGL Little Canada adventure centre, has not turned up on any CCTV footage.
Officers have spoken to nearby residents, and believe that Rosie may have had an argument with a colleague.
She never showed up for work on Monday, and her family have now flown in from Scotland to help with the rescue mission.
John Thorpe, 71, who lives near the adventure centre where Rosie disappeared, said police had searched his and his neighbours’ gardens, as well as a boat he keeps on the water.
He told Mail Online that the police “didn’t reveal too much but they said that she was in a distressed state just before she disappeared.”
Thorpe went on: “Neighbours have since told me that she may have had an argument with someone at the activity centre.”
He added: “It was late when she was last seen. It would have been pitch black at that time because there are no street lights.”
A family member at her mum’s house near Banchory, Aberdeenshire said on Thursday night it was completely out of character for Rosie to disappear without contacting her family.
“She may have had an argument with someone at the activity centre”
John Thorpe, nearby resident
He said: “She’s always very good at keeping in contact.”
The alarm was raised about the former Glasgow University student after she failed to turn up for her shift as a field studies instructor on Monday.
A ground search wasn’t launched until almost 40 hours later.
She was last seen by a creek close to the 50-acre camp, which backs onto water, at around 10.15pm on Sunday night.
Inspector Andy MacDonald, of Hampshire Police, said he believed she was “not the victim of crime”, but admitted he was “seriously concerned” for Rosie’s safety.
Rosie’s uncle, Labour MSP Daniel Johnson, appealed for information on Twitter.
Sharing two pictures, the Scottish Parliament Member for Edinburgh Southern tweeted: “My niece, Rosie, is missing. Could anyone with information please contact the police.”
Inspector MacDonald added: “We have searched an extensive area with quite difficult terrain as there is forest and water — a real variety of challenges.
He added that police believe “Rosie is still on the Isle of Wight”.