Yesterday, Sergeant Tony Woodbridge said police were still trying to determine how Sean Francis Lawson (20) drowned.
Police have appealed for information from the public, including any sightings of Mr Lawson or his white Subaru Legacy station wagon, in the Kakanui area.
A search was conducted in the area yesterday and some personal effects, some believed to belong to Mr Lawson, were found.
An Alaskan newspaper representative contacted Mr Lawson's mother at her home in Fairbanks.
The family was preparing to fly to New Zealand.
His mother, who did not want to be named, said her son was a concrete finisher who was taking a winter break to spend time with relatives during the New Zealand summer.
He had been in New Zealand for about three months.
"He was getting out of the Fairbanks winter . . . and having a good time enjoying the high country of New Zealand, going hiking in the hills.
"He ended up near the ocean one night after a raging rain storm. The river was swollen and he died," she said.
Police have said his family owned property in the Ohau area and he was helping get it ready to build on.
"We had a future that we were hoping for that's not coming about," Mr Lawson's mother said.
Sgt Woodbridge said an inquest would be held.
