Take the Discarded Knife to Quintis Jonespyre in Feathermoon Stronghold.
The Stronghold's resident druid, Quintis Jonespyre, has some... unusual skills. One of them involves psychometry - the ability to reveal an item's history by touch. Don't ask me how he does it; I chalk it up to magic I do not and choose not to understand. I do know, however, two things: one, I've seen it work and two, the bum owes me.
Take the knife up to Quint in his little tree-house here, and tell him for me that his Kalimdor Hold 'Em debt will be paid if he works his mojo on that knife.
Thank you, <name>.
While psychometry isn't an exact art by any stretch of the imagination, I've used it in times past to give insight into situations that others have chalked up to lost causes. I think using it on the knife you've uncovered will give us a glimpse into what happened to Raschal.
It will only take a moment to do, but it isn't what I'd call a caster-friendly task. Bear with me on this.
Upon completion of this quest you will gain: