Thompson said Robertson was “quickly identified as a person of interest”.
Robertson left the Pahīatua area shortly after his mother’s death, travelling by car to the Green and Blue Lakes area in Rotorua.
His car was found abandoned in the area, but despite an extensive search he was not located.
“Since Jeremy arrived in the Green and Blue Lakes area, there has been no activity on his bank accounts or mobile phone, and there has been no evidence found to suggest he was living rough in the area.
“Given these facts, alongside the passage of time, Police can now advise we believe the most likely scenario is that he died shortly after arriving in the Green and Blue Lakes area.”
Thompson said police were “committed” to finding Robertson if possible “in order to provide the closure that Karen’s family and loved ones deserve”.
“The investigation team is grateful to the support and assistance that local Rotorua staff have provided throughout the investigation.
Further searches are planned, and police urge anyone with information to come forward. Photo / NZME
“With their continued support, further searching is planned in a smaller, more concentrated section of the Green and Blue Lakes area, utilising specialist search teams and equipment.”
Police also wanted to thank members of the public who had come forward with information and possible sightings of Robertson.
“It is important to note that while the investigation team do believe it is strongly likely Jeremy died shortly after arriving in the Green and Blue Lakes area, we do still want to hear from anyone who believes they may have seen him at any time since October 15, 2025, or anyone with information which could be relevant to the investigation.”
RNZ earlier revealed that Robertson, who is believed to have had a history with mental health services, was planning to leave the home on the day Gilbert-Palmer died and take a bus to Rotorua.
Gilbert-Palmer’s niece, Barbara Evans, earlier told RNZ her aunty, who she called Narnie, would regularly message her talking about her son and his mental health.
Evans, who was adopted at birth, reconnected with Gilbert-Palmer and her grandparents about 30 years ago.
Evans said it appeared Robertson’s behaviour was “escalating” in the weeks before Gilbert-Palmer’s death.
Evans shared a series of messages she exchanged with Gilbert-Palmer.
On October 8, a week before she died, Gilbert-Palmer messaged Evans and said: “I tell u wat, he was better when he was on the drugs and vape, more chilled out. More aggressive now. [sic]”
She said her son was “dead against drugs now”.
The following day, Gilbert-Palmer said her son “has been nice for one day, now back to wat [sic] he was”.
In another message she wrote Robertson “can be so nasty at times”.
Gilbert-Palmer said she wished her niece didn’t live so far away so she could go and spend a few days with her.
Later that evening she messaged that he had “settled down”.
Then, on October 12, Gilbert-Palmer told Evans that her son was going to Rotorua by bus on October 15.
“He decided on hus [sic] own, to much stuff going on down here, having a go at people verbally.”
Gibert-Palmer said she would “fill in” her niece once Robertson was gone. It was the last time Evans heard from her.
In September, Gilbert-Palmer told her niece he was back home living with her as there was “nowhere for him to go”.
He’d previously stayed in Feilding but was “rude” to people there and “out does his stay”, she said.
Evans said she was “absolutely devastated” when she heard her aunty was dead.
Anyone who believes they have seen Jeremy, or has other information not yet provided to police, is asked to contact police via 105 and quote file number 251015/6286.
Information can also be provided anonymously via Crime Stoppers on 0800 555 111.
– RNZ