Police say the man was found on Monday after friends reported that they had not heard from him for days.
Unfortunately, the property in question was built on top of a series of lava tube tunnels.
When police went to do a welfare check to his Kaumana home at around 8.30am on Monday morning, it became apparent that the man had fallen through a soft spot of ground on his property, where he plummeted 7m to his death. The victim's identification has not been released because his relatives have not yet been notified.
A rescue team from the Hawaii Fire Department responded to the scene, where they managed to repel into the tube and retrieve the man's body.More news: Measles infection could 'reset' a person's immune system, studies show
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Mr Nishimoto was taken to the Hilo Medical Centre where he was pronounced dead, according to police.
The hollow core is created when the lava drains away completely.
An autopsy performed Tuesday confirmed that the victim died as a result of injuries constant with a fall.
Foul play is not suspected.
Hawaii Police Department Major Robert Wagner told Big Island Now that it "appeared [Mr Nishimoto] was trimming branches in his backyard" when falling into a 60 centimetre wide lava tube shaft. Lava tubes can be accessed when their roofs have caved in.