Police investigating an apparent murder-suicide of a couple in North Otago say they had no history of domestic violence and their deaths came "out of the blue".
Kim Gordon Simpson, 51, died in a crash on State Highway 1 about 4.15am on Thursday.
Police found the body of Lynette Mary Simpson, 52, when they went to the family home, about 3km away, to inform them of his death about 7am.
The couple owned the Olive Grove Holiday Park, in Waianakarua, 27 kilometres southwest of Oamaru.
Their sons, aged 20 and 17, were asleep in a sleepout at the property when police arrived.
A forensic examination at the holiday park continued yesterday, despite gale-force winds and torrential rain effectively trapping investigators at the scene.
Police said earlier they were treating the woman's "violent" death as a homicide and linked to her husband's crash.
Detective Senior Sergeant Malcolm Inglis said yesterday police were considering a few possible "triggers" of the deaths, but would not say what they were.
"There are some issues we're aware of but we're working through those and working with the family," he said. Mental health issues was "one avenue we are looking at".
Inglis said there was no warning the couple would die in such circumstances.
"It's quite out of the blue," he said. "We're not aware of any domestic violence.
"We're talking about a couple who, on the face of it, appeared to get on pretty well together."
The couple's sons had gone to Invercargill and were with their older sister and other family.
"It's a pretty traumatic time for the family," Inglis said. "It's very sad for them."
Police hoped to complete the forensic examination of the property and vehicle by today. "Obviously the weather is slowing things down a wee bit."
Inglis said earlier that firearms were not involved in Lynette Simpson's killing, and it was "part of the investigation" whether a knife was involved.
Police took Kim Simpson's firearms off him the day before the deaths, Fairfax Media understands.
No guests were at the holiday park at the time of the deaths.
A local woman, who asked to remain anonymous, said Kim Simpson had been "having a wee bit of a breakdown".
She wondered if the couple had been under financial pressure, as the holiday park was for sale.
- Fairfax Media
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