A student who went missing on Boxing Day had researched train journeys from her nearest station the day before she disappeared, her father has said.
Sophie Smith, 21, left her home in Gorleston in Norfolk, dressed in shorts and a vest top at 03:00 GMT. She left a note about taking her own life.
Martin Knowles said a computer search revealed she had looked at trains travelling away from Great Yarmouth.
This had given him "a glimmer of hope" that she was still alive, he said.
The last sighting of Ms Smith was on CCTV running towards the seafront in Gorleston after she left her home.
She had been receiving treatment for depression and anxiety.
The police, coastguard, Norfolk Fire and Rescue Service and Norfolk Lowland Search and Rescue scoured the area, before the search was scaled down.
Mr Knowles said the police told him there were no new leads at a recent meeting and "they are still under the impression that she's gone into the sea".
He added: "Not having closure is the most difficult part of it for me and the family.
"I will not give up until I hear otherwise - that she has been found in unfortunate circumstances or hopefully in a positive circumstance."