Untitled Sighting

Two buddies and I were camping on the top of Mt. Graham in an undeveloped campsite just past the turnoff for Riggs Flat Lake.  It was the middle of September, 1995. The first night we were sitting around our campfire at about 10:00 pm when we all heard a loud unidentified blood curdling scream.  It was like nothing we had heard before - not human or any other animal like an elk or something that we had heard before.  The noise came from about 200-300 feet in the distance.  We heard the scream about two or three times over the course of 15 minutes.  We all commented about the noise like, "what was that?"  But, we just kind of laughed it off. Later that night, at about 2-3 am, we were sleeping in the tent when we heard "something big"  creeping behind our tent.  It was definitely bipedal, because we could hear the pine needles crunching under the footsteps of whatever it was.  You could also tell it was big and had some weight to it.  We were so creeped out that I grabbed my 9 mm pistol and cocked it, and when we got the nerve we stuck our heads out of the tent and looked around.  Nothing was there. The next morning I looked for footprints, but couldn't see any because of the pineneedles covering the ground.  The next night the same thing happened at about the same time - something big on two legs was walking outside of our tent.  When we looked out it was gone.