Biologists say they still are not sure what killed a relatively young humpback whale before it washed ashore at Rye Beach on June 27.Snow Plow, an 18-year-old female, was first spotted by a fisherman 20 miles off Boon Ledge before it floated in with the wind.Experts performed a necropsy on the beach last Wednesday. They gathered several samples from various parts of the 45-foot whale.The samples are being analyzed at various labs as scientists work to determine a cause of death. They said there are still many questions left unanswered.Hundreds of people flocked to the beach to get a closer look at the mammal. The whale has since been removed.Scientists had been tracking Snow Plow for years.Humpback whales typically live 60 years or longer.Get the WMUR app