Officers were speaking to a large number of people, but were still urging anyone who might have information or CCTV footage that might assist the investigation to come forward.
"There are people in the community who know what happened," Leigh said.
The Otago Daily Times understands Buis was scheduled to appear in court for an alleged breach of sentence a couple of days before his death.
He had been before the court several times in recent years and his chaotic lifestyle was apparent after a month-long crime spree a year ago, during which he repeatedly evaded police.
That began with the theft of an expensive bottle of port from a Kaikorai Valley Rd shop and, a couple of weeks later, progressed to a police chase through Christchurch.
Buis narrowly missed patrol cars and civilian vehicles during the pursuit and reached speeds of 120km/h in a 50km/h zone before officers pulled back.
Days later, on August 6, Buis was seen in the same Mazda in the driveway of his Mornington home - less than a kilometre from where he would die almost a year later.
After being placed under arrest, he took off at speed, taking corners at such a clip he was on two wheels at times.
Buis' driving was too dangerous for police to follow but they found him half an hour later.
This time Buis fled on foot and while running down a grassy hill, dropped a shopping bag containing 0.8g of methamphetamine, arthritis medication, 3.3g of cannabis, digital scales, ziplock bags, seven glass pipes and a blowtorch.
When police searched the Mazda, they found a tick list featuring names and dollar figures relating to drug debts.
Buis was finally arrested a couple of weeks later after putting a rock through the window of his ex-partner.
Before the Dunedin District Court in January, he was sentenced to five months' community detention, 12 months' intensive supervision and was banned from driving for two and a half years.
