(Wood Village, OR)  --  Investigators say a 16-year-old kidnapped his great-grandmother with two other teens so he could kill her.  Investigators didn't disclose why Dylan Martin wanted to take the life of the 86-year-old woman.  Martin and 15-year-old Billy Underwood along with another 14-year-old girl kidnapped Hazel Abel in Kennewick, Washington on Monday and threw her in the trunk of a car.  Abel escaped when the three stopped at a Wal Mart in Wood Village.  Underwood and Martin are facing numerous charges, including kidnapping and robbery and investigators say they're being charged as adults. The other teen involved was not identified.