Park chief Teekhawuth Sriburin said on Sunday (Jan 22) that the dead man, believed to be suffering from depression, jumped off a cliff as he was being escorted off a nature trail in Khao Ngon Nak by park rangers.
The incident happened so quickly the rangers had no chance of stopping him, the Bangkok Post reports him as saying.
Mr Teekhawuth said the rangers went looking for the man - identified as Loo Kevin Andre, 31 - after park officials received a phone call from a man claiming to be Loo’s father, asking them to look for his son, whom he said was suffering from a major depressive disorder.
Park rangers at the Thap Khaek forest protection unit checked their logbook and found that Loo had gone out hiking at 11:12am.
After about six hours of searching, rangers found Loo about 5:30pm and talked him into coming to their office with them, to which Loo agreed.
On the way down, around 6:30pm, about two kilometres from the location where he was found, Loo asked to stop for a quick break. He sat down to receive a telephone call, after which he apologised to the rangers before running off a cliff.
The rangers went to Ao Nang police station to file a report before contacting rescue units to search for Loo. His body was found around 1am and was transferred to Krabi Hospital around 6am on Sunday for an autopsy, Mr Teekhawuth said.
The 3.7-km nature trail on Khao Ngon Nak mountain, about 500 metres above sea level, is popular with adventure-loving tourists.
If you or anyone you know is in need of emotional support and counselling, please contact the Samaritans of Thailand at their 24-hour hotline 02-113-6789 (English & Thai) or the Thai Mental Health Hotline at 1323 (Thai).