A Storm of Swords - Jon XI

That startled him. "Why?"Stannis snorted. "I know Janos Slynt. And I knew Ned Stark as well. Your father was no friend of mine, but only a fool would doubt his honor or his honesty. You have his look." A big man, Stannis Baratheon towered over Jon, but he was so gaunt that he looked ten years older than he was. "I know more than you might think, Jon Snow. I know it was you who found the dragon-glass dagger that Randyll Tarly's son used to slay the Other.""Ghost found it. The blade was wrapped in a ranger's cloak and buried beneath the Fist of the First Men. There were other blades as well . . . spearheads, arrowheads, all dragon-glass."A Storm of Swords - Jon XI