I was playing my evil cleric, just hiding amongst a party of do-gooders, as a follower of Cyric do, and had recently leveled up to where I could now cast Touch of Death(?), a touch attack spell that has basically a 50/50 chance of straight up killing your target and I happened to be talking to an NPC, all alone, that was crucial to the rest of the party’s plans. Naturally I tested out my new spell.
The party investigated, of course, but none of them were spell casters or had enough ability to discern anything. Including interrogating me, since I also had +30 to deception due to some special feats and items I earned previously in the adventure. Since we play entirely online, only the DM and myself knew the truth as the events. Up until my ultimate reveal toward the end of the campaign, they suspected nothing. That was a fun-ass game.