An elderly man has died after falling into a 6.7-metre deep "lava tube" while trimming tree branches in his backyard in Hilo, Hawaii.
Hawaii Island police said on Wednesday (local time) the man had been identified as 71-year-old Robert Hisashi Nishimoto.
Police said they were called to the man's property on Monday morning (local time), following reports that Mr Nishimoto "hasn't been seen or heard from in several days".
Lava tubes are natural underground tunnels that form when volcanic lava flow cools down at the top surface creating a crust while remaining fluid on the inside, allowing the lava to flow and drain.
Hawaii is well-known for its active volcanos and lava tubes as the Hawaiian islands were formed by volcanic activity.
Police said it looked like Mr Nishimoto "had fallen through a soft area of ground" into a lava tube in his backyard.
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.
A rescue crew with the Hawaii Fire department managed to abseil into the lava tube and lift Mr Nishimoto out.
Mr Nishimoto was taken to the Hilo Medical Centre where he was pronounced dead, according to police.
Police said an autopsy showed the Mr Nishimoto died "as a result of injuries consistent with falling."