Jon, 44, was last seen in Dalmore on Tuesday last week wearing brown shorts and a charcoal hoodie.
His family has since been out searching North Dunedin and putting up posters appealing for information.
Operation controller Sergeant Nathan White said while it was still unclear where Jon had been heading, LandSAR were attempting to narrow down the search area.
Police knew Jon left his home in his car on Tuesday last week and his car was subsequently found near Chingford Park on Monday.
‘‘We really don’t have a lot of information between those two timeframes. We need more information to progress the search really, so we can actually target some areas.’’
Overnight, police had received half a dozen responses to their plea for information and were combing through about a week’s worth of CCTV footage.
They had identified multiple areas around where Jon’s car was found, and about a dozen of those were covered by CCTV footage.
‘‘It’s quite a big job — we’re potentially looking at a week’s worth of footage.
‘‘If we can get a bit of a sighting that’s 100% him, and we’re confident it is and it’s reliable . . . that would be gold.’’
While there were no active LandSAR searchers in the field today, the family was back out searching today.
They had been active part of the search effort with some skilled in the outdoors and other applicable skills, Sgt White said.
On Tuesday, about 30 people were involved in a search and rescue operation around Chingford Park.
Their resources were largely volunteer-based, Sgt White said, so they needed ‘‘concrete areas’’ to focus their search efforts.
Jon had proven himself to be ‘‘quite fit, and capable of walking some good distances’’, he said.
‘‘It’s a big search area at the moment . . . could be anywhere.’’
Family remaining "stoic".
The man’s stepfather, who did not wish to be named, told the Otago Daily Times that family, friends, two LandSAR volunteers and two dogs had searched around North Dunedin yesterday.
"Well, the bottom line is we did not have any success yesterday, but the search in actual fact went really well."
The group broke into small groups, had road watches, swept through a large area of North Dunedin and had LandSAR dogs on the trail as well.
So far, the searches had not been fruitful, but he was thankful for the police response and support.
The stepfather said Jon was very recognisable in the North East Valley area, due to the amount of time he spent walking back and forth between the university campus and Normanby.
He often called in to cafes and shops with his son and walked his dog up and down North Rd.
"That was his neighbourhood for 14 years. He would just go about his life like any other person."
The stepfather said the family had an idea of why he had gone missing and said it was "definitely stress-related".
They were remaining optimistic and "stoic" as the search continued, he said.
He urged the public to stay on the lookout for Jon.
"Please keep your eyes open in the wider Dunedin area."
He said the posters had helped and they had received a few calls, and urged the public to keep the calls coming in if they spotted anything.
Yesterday, police released a CCTV image of Jon, taken in Castle St the day after his disappearance.
The discovery of his white Nissan Bluebird on Monday sparked a search and rescue operation of the park and the surrounding area on Tuesday.
Senior Sergeant Anthony Bond said police were contacting the man’s bank to determine if there had been any recent transactions.
Police also had his cellphone and would search the device for information that could aid in their search.
Police were following lines of inquiry, he said.
- Anyone with information on the man’s whereabouts or with CCTV footage are urged to contact police on 111 and quote file number 240317/7508.
