The 23-year-old up-and-coming chef has been missing since August 23, when he was swimming and got into trouble.
Another friend jumped in the water to help him, but both began getting swept downstream.
A third friend, a woman who was also on the beach, saw the pair drifting off and ran down the ramp to try to help them, and called emergency services.
Kohu's friend managed to swim to the other side and climb up an embankment and also call for help.
But Kohu was unfortunately lost.
On the night Kohu went missing, the police boat, Waikato Westpac Rescue Helicopter and the Fire and Emergency drone all carried out searches, to no avail.
The police national dive squad also joined the search in the days after his disappearance.
His cousin, Te Hikuwai Kohu, earlier told the Herald she did not understand why he was swimming at that hour.
"He was really smart and he was a black belt at 11 or 12, he used to do karate growing up, he was smart as.
"He was pretty mature for his age, he didn't drink, well I thought he didn't drink."
To hear that he was down swimming at the river on Sunday night was a shock, she said.
"And he knows that he's not allowed in the river."
She said her cousin should have known that as his nan - victim advocate and psychotherapist Hinewirangi Kohu-Morgan NZOM - had always told him to steer clear of it.
Kohu, originally from the Bay of Plenty, had been working at Camarosa Restaurant on the outskirts of Hamilton, with renowned chef Andrew Clarke.
Kohu had followed in his father's footsteps and become a chef after initially dabbling in the plumbing trade.
"He always cooked for us. He taught himself, he didn't have a qualification or anything he just learned from the bottom like from being a dishwasher and worked his way up," Te Hikuwai said.
His death has been referred to the Coroner.
