Hints of Cult Activity - NWN Side Quest (Chapter 1)

Hints of Cult Activity is a side quest that will begin sometime after turning in the first reagent cure to Aribeth. A group of Hired Thugs will appear at a specific location and attack you, when you loot their corpses you'll find an Anonymous Letter which will start this quest when you loot it.

Below is a list of all 4 locations you can encounter this group of Hired Thugs. They will always spawn in with a puff of smoke and attack when you enter their trigger radius.

Peninsula District: Outside of the Prison
Beggar's Nest: Outside of the Shining Serpent Inn
Blacklake District: Northern No-Man's-Land
Docks District: Out front of the Seedy Tavern

To complete this quest all you need to do is take the Anonymous Note to Fenthick and Desther inside the Temple of Tyr. You can find both of them in the Sanatorium portion of the Temple of Tyr, a screenshot of their location can be found below. Give the note to Fenthick to complete this quest.