In my Hunter the Vigil chronicle, the players were doing a good job of not talking to people, and IMHO, abused one of my NPCs, Ariana, to "go do it for them". It refers to investigating a Demon, Sarah, who was manifesting a glitch. I decided that Ariana's primary motivation for being in town was her quest for vengeance, against a Vampire, Scratch (from the Chicago book), so she ends up making a deal with the Sarah to get her vengeance, which she does.
However, I've allowed a PC Vampire to join the game (only one). He ended up doing a search for Scratch and got an exceptional success. I decided that he finds Ariana having recently torched Scratch. His character is a Ventrue and not well suited for combat, He decided to Dominate Ariana into thinking He did it and that she got their too late. She's now feeling like she didn't get her end of the bargain.
It's worth mentioning that Sarah, the Demon, got the friendship with the other PCs. However, Ariana neglected to mention that they knew about Scratch, and so when they talking about how they were looking for scratch, and Sarah compensated poorly, they got tipped off that something was awry. They are suspicious, and last session were talking a kidnapping Sarah. Sarah also doesn't know about the shared friend Max who didn't get included in bargain.
Sarah, is a Destroyer, Tempter. Is their any way she can know that Ariana's memory got subsequently modified by the PC Vampire?