It was the beginning of the work day and Mr Bakis Jaujan was cleaning the inside of a cement mixer.
But his colleague - unaware that Mr Bakis was inside - turned on the lorry's engine, causing the mixer to turn.
It is understood that the colleague realised Mr Bakis was trapped only after another worker shouted at him. But it was too late.
Mr Bakis was crushed as the machine started turning and died moments later.
His colleagues at the construction site in Sandakan in the Malaysian state of Sabah could only watch in horror as the tragedy occurred at 9am on Wednesday morning.
Sandakan deputy police chief Superintendent Fadzil Mohd Ali told Malaysian daily Harian Metro on Thursday that after the engine was switched off, workers rushed to Mr Bakis' aid but he was already dead.
Investigations are ongoing but no foul play is suspected, he added.
The case is being classified as accidental death.
Mr Bakis' remains have been sent to the Duchess of Kent Hospital in Sandakan for a post-mortem, police said.
Sandakan Fire and Rescue Station operation chief Devi Rashedee Ensoi told Harian Metro they took about an hour to extricate Mr Bakis' body from the cement mixer.
He said: "We had to cut the metallic parts of the machine to pull the body out before handing it over to the police."
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