Tuia 250 celebrations took place there later that day.
Mr Kerr says he is “very confident” the mystery of what happened to Jamie can be solved and that members of the community hold vital information.
He recently set up an 0800 phone line (0800 123 114) and an email — FindJamie@scope.co.nz — so people could get in touch confidentially.
Mr Kerr also wants people, community and media organisations to hunt out any photos of the Tuia 250 event at the wharf that weekend, particularly those showing the carpark and crowd shots.
Shots can be shared — again, confidentially — through the FindJamie email.
Jamie's car, a blue Nissan Tiida, is an important focus of his investigation. She frequently called on her grandfather Eru Kaiwai to jump start it as the car had a faulty battery and needed to be driven at least once every 12 hours or so.
Eru went with police to retrieve the vehicle from the wharf carpark on the afternoon of October 13, 2019, and oddly, it started straight away. The family say this disproves the police theory it was in the same place at the wharf carpark for five days.
Mr Kerr says photographs could hold crucial clues about the movement of the car, including who was driving it, how it came to end up at the wharf and who might have been standing near it before it was retrieved that afternoon.
But he stresses any photos are of interest. They do not have to include the vehicle.
He and Jamie's family question the police theory that Jamie went into the water at the wharf.
The family has been critical of the police investigation, which they say failed to follow usual lines of inquiry after police decided from the outset they were dealing with a suicide.
Mr Kerr says evidence reviewed by him to date does not remove the possibility foul play was involved.
The fact the police undertook an extensive and detailed 10-day ocean and seabed floor search of the area but found nothing strongly suggested Jamie was never in the water, he said.
It is possible the only sighting of Jamie on the beach at Tolaga Bay on October 11 could be mistaken or incorrect, Mr Kerr says.
Jamie's cousin Jonique Oli-Alainu'uese has led the family's pursuit to get justice for Jamie.
Earlier this year, Jonique lodged a formal complaint about the police investigation, which she says was “”.
The Independent Police Conduct Authority (IPCA) told The Gisborne Herald the complaint had been assessed and did not result in the authority initiating an independent investigation.
“The authority agreed with police that police should review the investigation and upon completion would notify the authority of their findings, and communicate the outcome of the review to the designated point-of-contact identified by the family,” an IPCA spokesperson said.
Mr Kerr said despite Jonique's lead role in the case as a representative of the whanau, police had now enlisted as the family “point-of-contact” Jamie's mother, who lives in Rotorua and from who Jamie was estranged for several years.
Jamie went to live with her grandparents in Tolaga Bay when she was a teenager.
Mr Kerr says he and Jonique do not know what police have told Jamie's mother about the investigation and its current status.
The Gisborne Herald was unable to contact her.
The police officer in charge of the case, Detective Constable Sean Burgess, did not respond to a request for an update as to the current state of the police inquiry.
Earlier this year, Detective Senior Sergeant Kevin Ford said the case was still open as a missing person inquiry but being prepared for transfer to a coroner.
He could not give a timeframe for when that might happen.
