Kathmandu - Nepal has opened an investigation into an Indian police couple accused of falsifying photographs to support their claim of summiting Mount Everest this year, an official said on Monday.Indian police constables Dinesh and Tarakeshwari Rathod earlier told reporters they had reached the 8 848-metre peak on May 23, but their claims were thrown into doubt after fellow climbers accused the couple of doctoring photographs of them on the summit."We have started an investigation into the Indian police couple's claim of scaling Mount Everest," said Nepal tourism chief, Sudarshan Prasad Dhakal.The tourism department initially certified the couple's summit claims after speaking to their expedition organisers and to government officials stationed at Everest base camp, Dhakal told AFP."In order to provide a certificate to the climber, we rely on their photograph on top of Mount Everest.... If someone fakes their photos, it's hard to determine that they are not original," Dhakal said."If proven guilty, we will invalidate the Indian couple's certificate and charge them with forgery and fraud."The probe began on Sunday evening, he said.It is not technically an offence to pretend to summit Everest, but authorities are investigating the couple for fraud after eight other climbers filed a complaint against them in India, saying such a con belittles the efforts of genuine mountaineers.Many successful summiteers have gone on to make money or forge careers as motivational speakers and authors on the back of their feat.A total of 456 people, including more than 250 foreigners, summited Everest during the recently-concluded spring season after two consecutive years of deadly disasters that led to almost all attempts being abandoned.Mountaineering is a major revenue-earner for the impoverished Himalayan nation and this year's string of successful summits is expected to boost the industry, which was left reeling after an earthquake last year killed almost 9 000 people nationwide.Hundreds fled Everest last year after an earthquake-triggered avalanche at base camp killed 18 people.Only one climber reached the top in 2014 after an avalanche killed 16 Nepali guides that year.