An Alaska State Trooper helicopter carrying two troopers and a rescued snowmobiler crashed Saturday night in the south-central part of the state, and no survivors have been found, an agency spokeswoman said. Trooper spokeswoman Megan Peters said the crash site was spotted Sunday, but she could not immediately confirm that the three on board were killed. Wreckage of the helicopter burned, but Peters said it was not known how the fire started or how long it lasted.