I'm very new to the Inquisition myself, but I suppose if it were up to me I would do much as you've done so far -- air it to the Inquisition presence in Kirkwall at large, increase the number of people on the lookout. If there's a thief, he'll already know to be wary if he's not a fool.

[Julius considers a moment, then adds:]

And I suppose there's no sense ruling out carelessness too soon.

[Not everyone is paranoid.]