It may never be known exactly what happened at Lake Tekapo on board a small pleasure boat that resulted in one man dying and two others still missing.
But what is known are some grim facts - the lake often does not give up its victims, with at least seven bodies never recovered The three South Canterbury men went out at mid-morning on Wednesday in a 4m cabin cruiser, intending to head up to the top of the lake for a day's fishing at the McCauley River mouth.
However, in the early afternoon they all ended up in the water.
The body of Alexander Haywood (72), of Pleasant Point, was recovered from the shore of Motuariki Island.
His son, Antony (46), and Murray Green (54), both of Timaru, are still missing.
Their boat, filled with water, was found by an air force Iroquois using night vision equipment about 3.30am on Thursday, stuck on a sand bar on the Cass River delta.
Water was pumped from the boat and it was put on its trailer late on Thursday afternoon, then inspected by two Maritime New Zealand inspectors.
Senior Constable Brent Swanson, of Tekapo, said yesterday there was no obvious cause of what had led to the death of one man and the probable deaths of the two others.
The boat hit the sand bar with the throttle on the Johnson 90hp outboard motor wide open.
"But whether they were on board at the time, we don't know. It hasn't answered any questions; it's created more questions," he said.
The boat had not been sufficiently damaged when it hit the sandbar for it to sink.
What happened was "a real mystery", Snr Const Swanson said.
He said the initial assessment by Maritime NZ indicated the boat, at high speed, might have hit something - possibly a log or tree - in the water.
It was possible the three men were thrown out.
The fact the boat was still at full throttle and the engine appeared to have run for some time after it hit the sandbank added to that.
"Your instinctive reaction is to shut the engine down as soon as you hit something," he said.
On Wednesday, between 35 and 40 people were involved in shoreline and water searches, along with the Westpac Rescue Helicopter.
Early on Thursday, there were hopes the two missing men had made it to shore, but were unconscious or unable to reach searchers.
However, that hope dwindled in the afternoon when the searchers failed to find any signs of the men.
Yesterday, it was decided there would be no further searching, although family friends did search some areas by boat.
The searches on Thursday had been thorough enough to have either found the two men or their bodies, it was believed.
Snr Const Swanson said an aerial search would be conducted towards the end of Labour Weekend, about the time they would be expected to return to the surface.
However, Lake Tekapo had a reputation for not releasing bodies of victims - local people estimated at least seven were still missing, he said.