(Portland, OR)  --  The Oregon Department of Fish and Wildlife says it's tracking a cougar that killed a Gresham woman who was hiking near Mount Hood.  Department officials say they sent some of the cougar's DNA to a lab for testing yesterday.  They plan to use mules and dogs to try to track down the cougar and kill it.  Diana Bober was hiking along the Hunchback Trail near the Zigzag Ranger Station last week when the cougar attacked her.  It's the first fatal cougar attack on a human in the wild in Oregon's recorded history.