Kathmandu, Nov. 12 :    Kathmandu, Nov. 12:  The sister-in-law of Nepal's King Gyanendra died in a helicopter crash today, a new tragedy for a royal family still mourning the massacre of most of its members in June, officials said. Princess Prekshya, Queen Komal's younger sister, was one of the six people on board a helicopter that crashed into the Rara Lake, some 550 km northwest of Kathmandu. Princess Prekshya Rajya Lakshmi Devi Shah was married to the late Prince Dhirendra, the youngest brother of the king.