India has been gripped by claims of attempted murder and professional jealousy against one of the world's richest men, as a technician who uncovered the alleged plot was found dead.

Bharat Borge, a senior technician with Air Works India Engineering, last week discovered sand and stones in the fuel tank of a Bell 412 helicopter belonging to the wealthy industrialist Anil Ambani.

Anil Ambani ... plot to kill him. Credit:AFP

But in a twist worthy of a crime novel, Borge's body was found on a railway track in a Mumbai suburb on Tuesday evening, according to police, who said a note was recovered and the case was being treated as suicide.

Indian media reported the note was to a detective who had questioned Borge, and also claimed that before his death Borge had received visitors from the Reliance Anil Dhirubhai Ambani Group (R-ADAG), of which Ambani is chairman.