Investigating through Sharn
Rethlin and Kae go fletcher hunting. Several hours later, they have amassed the following facts:
The arrowhead is originally a Karnathi design: mind you, any master fletcher can make them.
There are a half-dozen places in Sharn that sell arrows like that, either by making them themselves or importing them from elsewhere -- Karnath, presumably.
The McCallack brothers are triplets: a human, a half-orc, and a half-elf. Nobody asks about their family life.
The Brothers run a successful industrial forge: cogs, barrel hoops, chain, wire, nails, hinges, locks, etc. As far as anyone knows they don't make weapons, but they could if they wanted to.
Now, the library.
The library at Mourgrave U used to be friendly and welcoming. But in the last year they've had two robberies here, at least one of which also involved a murder.
As a result, there's a long line outside the library as people's person's and bags are checked by some assistant professors, backed up by polite mercenary swordsmen.
Signs declare No Weapons Allowed in Library and Please Leave all Bags at Counter.
The line consists of scholars and students from all over Khorvaire talking, fretting, or grumbling.
A trio of halflings arrive pushing a handcart, which unfolds into a small noodle cart and drink stand. Business surges, as people resign themselves to spending a long time waiting to study.
"Buy our noodles! They're dreamy good and build brainpower!"