The bodies of a woman and three children found in an Ashburton house this afternoon will remain at the property overnight, under police guard.
Police, who have a team of 30 working on the investigation into the deaths, said that the four bodies can not be moved until pathologist and police examinations are completed in the morning.
Mid South Canterbury Police Area Commander Inspector Dave Gaskin said the scene posed a number of questions for investigators.
"This is a tragedy and there are a number of questions we are looking for answers for. Our thoughts are with the family at this time."
A neighbour told Checkpoint earlier that the people who died were not the usual occupants of the house.
The woman, who did not want to be named, said she suspected that the deceased, whose bodies were discovered about 4pm, might be her neighbours' daughter and her children.
"They don't normally live next door so it blows me away. They're not normally the occupants of the house, put it that way.
"There was a couple who lived there with an elder boy."
The neighbour said she believed a car parked at the property on Thomson Street belonged to the usual residents' daughter.
The daughter visited sometimes and the neighbour would hear young children playing.
"I don't know the daughter; I just knew she had little children."
Mr Gaskin said the alarm was raised when people who knew the deceased entered the house this afternoon and discovered their bodies.
"I understand it was some people who live in the house who have been away for a period of time and came back and found them in the house," Mr Gaskin said.
Police entered the house but thought they smelled LPG so left the property.
"The police have made an initial entry and then afterward have gone and got the fire brigade, because they thought they smelt gas but weren't sure."
The neighbour said she saw people in protective suits and gas masks.
The fire service did not detect gas and the police have now re-entered the home, Mr Gaskin said.
"Now, they're going in to have a more detailed look... I know we have officers [in the house] from Ashburton, Timaru and officers from Christchurch are also travelling to the scene."
The neighbour said there was police activity in the property's garage.
"They've [the police] opened the garage door up - that's maybe where it's happened."
Mr Gaskin said the deaths were being treated as suspicious, but the police were not focused on foul play.
"There is no indication, from what I understand, that foul play has been involved, but we're keeping an open mind at this stage."
Earlier, neighbours were asked to leave their houses and a cordon was put in place around the area.
They have now been allowed back into their homes, but have had to leave their cars outside the corden.