A Czech tourist appears to have been sexually assaulted before she was killed on a forestry block near Waimate, police say.
Dagmar Pytlickova, 31, who was known as Dasha, was found dead in the remote South Canterbury forest next to the body of Jason Frandi, from Waimate, on Sunday.
Ms Pytlickova had been in New Zealand since January this year, and most recently had worked at a vineyard in Cromwell in Central Otago.
Police believe she had been hitch-hiking from Cromwell to Timaru and is likely to have encountered Mr Frandi, 43, somewhere between Omarama and Kurow.
On Wednesday, police said that initial results from a post-mortem showed that Ms Pytlickova died from a severe wound to her neck and there was evidence that she had been sexually assaulted.
Police said wounds on Mr Frandi's left wrist most likely caused his death.
Detective Inspector Greg Williams said it was was possible Mr Frandi was alive for a period of time after the woman died.
Mr Williams says Ms Pytlickova's bags have been found in Mr Frandi's car and the last reported contact with her was at 5.45pm on Saturday.
The investigation will continue for several days and a file is being prepared for the Coroner.
In 2000, Jason Frandi was jailed for three-and-a-half years for abducting a young woman whom he did not know and intended to rape.
Frandi had been sought by police
Police have revealed they were looking for Jason Frandi the day before the digging contractor was discovered dead and investigating an altercation involving him following an accusation of child abuse made against him recently.
Assistant Police Commissioner Malcolm Burgess said it is hard to say whether police could have prevented the killing of Dasha Pytlickova if they had acted earlier.
Mr Burgess told Morning Report on Wednesday that police tried to find Mr Frandi as soon as they knew he had learnt of their current investigation.
He said police had not approached Mr Frandi earlier, because they were still gathering evidence against him.
Czech ambassador Hynek Kmonicek says New Zealand is a popular destination for young Czech people.
Mr Kmonicek told Morning Report Ms Pytlickova's death is a strong reminder of the dangers of hitch-hiking, but New Zealand is a relatively safe country.