A truck driver who took his own life days after a fiery crash claimed the life of three people was "broken hearted".
Findings released by the coroner into the fatal crash on the main street of Patea in February last year revealed truck driver Michael Fairclough ended his own life soon after his tanker ploughed into the back of a parked car, killing all inside.
Those who died were driver John James William Bayne, his sister Cherylene Alison Bayne and Chantelle Giles.
No one saw the smash, but those nearby, including Giles' husband Raphael, heard a large explosion as the tanker drove into the back of the car, dragging it along the road.
Powerlines were strewn across the ground and 2m high flames quickly enveloped the wreckage.
Coroner Christopher Devonport said it would remain a mystery why the fully laden milk tanker veered off the road and ploughed into the back of a parked Honda Civic.
Fairclough's widow told the coroner that after the crash her husband was "a man with a broken heart". He took his own life on February 27-28.
Senior crash analyst Les Maddaford said the reason for the crash would "remain unknown and speculative at best".
Data from the truck was destroyed in the intense blaze that erupted in the moments after the crash and despite extensive investigations, Maddaford was unable to find out why Fairclough's truck veered off the road and crashed into the parked car.
A woman who lived close to the crash told police a shocked Fairclough said a wasp had flown into his cab.
He had also recieved a text on his phone earlier in the afternoon, but it was not clear if he had read it.
However, Fairclough told a doctor who examined him at the scene and police later in hospital he was not sure what happened and the only thing he could recall were flames and a powerpole.
But Devonport said it was speculative as to whether he was viewing a text on his phone, fell asleep, suffered a medical event or distracted by an insect.
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