Ace mountaineer Malli Mastan Babu, who went missing during an expedition in the high mountains between Argentina and Chile last month, has been found dead.Mastan Babu's sister Dorasanamma said, government officials had conveyed the news to the family members.Hailing from Nellore in Andhra Pradesh, the 40-year-old accomplished mountaineer had gone on an expedition around a fortnight ago.He went missing as the weather turned bad. He reportedly holds a record for being the fastest 'seven summit' climber from India.