Search for Heirloom bounties

[Tyrath]

What are the mechanics of finding heirlooms when searching for them? Are they in a specific room, or does each search you do have a random chance of finding the item? Can I just sit in the same room and search until I find it, or do I have to move from room to room (I have been doing the latter, but needing to cast Spirit Fog every room I move to is kind of a pain).

[Rucca]

I have never tried searching one room over and over, so not sure if that works or not. I have tried just searching a small area over and over, like maybe six rooms, and finding the heirloom. So I do know it isn't in a specific room when you start out looking for it.

[Rhovan]

I've tried searching the same room for about 20 times without success, but that is far from conclusive that you cannot find an heirloom that way. However, I can say that searching back and forth between two rooms works very well.