Bangladesh, Jan. 28 -- Nepalese authorities have arrested six senior executives from three prominent mountain rescue agencies, accusing them of orchestrating a large-scale insurance fraud scheme involving hundreds of staged helicopter evacuations of foreign trekkers from the Himalayas. Investigators say the alleged racket siphoned off nearly $20 million from international insurance companies and inflicted serious reputational damage on Nepals vital tourism industry.

A court in Kathmandu on January 26 granted police five days of custody to question the suspects, who were detained as part of an expanding investigation led by the Central Investigation Bureau (CIB) of the Nepal Police. Prosecutors allege the executives systematically arrange...