You recognize this oil. It is a thick polishing compound. You use it on metal when you want to polish it to a high gleam. It is thick and put on when you are done with a blade and want to polish it. You also know it stains everything, it is likely the same as the cuts.

Curascious puts the blade to the tip of his tongue, then spits. "Metal polish. Stains everything."

Mozu considers for a moment. Does it seem like similar substances found with the blacksmith, or perhaps... “Would it be used in engraving?”

"Who is I? I is Tithenraug, the wittle demon and lead inestergator in solving who killed yer boss. We fink 'e was murdered and it were made tah lookin like he knifed hisself." Tith casually sets his hand on the heads of his axes "I lookin teh see 'ow dee orcs gotted in inna first place."

Quote from JcAndD >>

Mozu considers for a moment. Does it seem like similar substances found with the blacksmith, or perhaps... “Would it be used in engraving?”

 “No engraving,” shrugs Curascious, and holds the knife out to show that it isn’t engraved. “And no, not what it’s for. For keeping metal shiny, sharp, undamaged. Proper blade maintenance.”

Quote from Hardcopi >>

Mozu's spell reveals that the Rodrik was poisoned with a poison called "Oil of Taggit". It is a poison that causes paralysis and unconsciousness. It is not however on the wound. Nor is it on the hopeknife. It would appear to be ingested at some point. It takes time to work, but would have to have ingested it within 1/2 hour of it knocking him out.

"Messers," Herd interrupts, "I believe Mr. Mozu made mention of some poison - he said it under his breath after casting his spell. Should that not be the new point of interest? Who was with Mr. Rodrik half an hour or so before his death?" 

Mozu looks over the wounds, “If he was unconscious, then even the most unskilled child would have been able execute him. Tell me, gnome, one commonly finishes the polish before using the blade, correct? If that’s the case, then it would seem that the blade could have been stolen while it was being crafted...”

“Good point, good point,” says Curascious. “Yes, the polishing oil would not be left on the blade. Big mess otherwise. Maybe we go examine the suspects, find stains, find the murderer?”

Mozu snorts, “The apprentice of the blacksmith was last seen with it. It stands to reason that they could have been mugged.”

"We should also find out how common this," Oil of Taggit" and where access to such a poison could be found," suggest Herd. 

//Where do you want to go and who do you want to talk to?//

The guards look down at the little goblin. "Look, we don't understand a word you are saying. You need to relax." He begins to unsheath his sword. "Let go of the axe."

// Everyone else make a perception check, DC 13 to see if you hear the commotion.//

 Perception: 13

Looking around, Red realizes Tith is not here. "Oh dear, I think our goblin friend has done something....rather rash. "

//Well Red definitely hears about a block away guards raising their voice and what sounds like the voice of Tith saying something.//

Quote from DarthAvarice >>

 Looking around, Red realizes Tith is not here. "Oh dear, I think our goblin friend has done something....rather rash. "

 “Oh no...” Curascious looks around for the source of commotion.

Mozu has a set brow right now as he silently starts looking for the goblin.

Red heads in the direction of the commotion. 

You round the corner and see Tith surrounded by several guards. All of which have their hands on their hilts.

"Now we don't want any trouble." The lead one tells Tith ."How about we just talk."

Red approaches the guard "is something wrong? Tith here is helping with our investigation. Has he discovered something? "

"I'm trying to talk, an you surrounded me first... dat tends to make one edgy. Oh hi Red" Tith is very relaxed, it's not the first time he has been surrounded and seems rather nonchalant about the whole affair.