"I see where you're going with this," says Laine, "but you're wrong. We got all the clues off the hobos; I'll look into any other humans just as soon as we're done looking into everything else right here; and the only other humans we have clues on around here are you, me, and my buddies, and we all clearly got here well after the Furlbrows died. Ask anyone you like or look at our footprints."
Follow Laine's advice. See what you can find around here on your own. It's clear to everyone here that the gnoll and murloc clues are worthless. Offer to look into the other humans yourself.