Game Of Thrones served up another shocking episode on Sunday night with what fans are now calling “The Purple Wedding”; by now, most people are aware that a major character was killed off, but there’s an air of “whodunit” that has fans who haven’t read the books taking to social media.

“By the time you get to the ninth episode, the end of the season, it’s expected that something momentous is going to happen. Doing something this world-changing in the second episode seemed fun to us,” said showrunner Dan Weiss.

If you’re one of those who caught some seemingly random details in Sunday’s episode, you may not be surprised at who the killer is reported to be. (WARNING: SPOILERS AHEAD) Although Joffrey pointed at his uncle as he lay dying from the poison he’d ingested–and although Tyrion had many reasons to kill the spoiled king–it’s the loving gesture of a grandmother that points to the actual killer.

As Kotaku points out, Olenna Tyrell–grandmother to Queen Margaery–slyly garnered several pieces of jewelry for the wedding and proclaimed them not special enough for the big day. She even threw one over the balcony. In one perplexing scene in the season opener, Sansa Stark is approached by Ser Dontos and given a necklace with seven purple crystals dangling from it. That necklace is worn by Sansa at the wedding, and when Olenna approaches Sansa at the table to give her condolences regarding the horrible deaths of her mother and brother, she touches the crystals around her neck. It’s presumed that Olenna had the necklace made, got it into Sansa’s hands, then took the crystal from it–a poisonous sparkler called “The Strangler”–and dropped it into Joffrey’s cup.

As someone who’s late to reading the books, I’m thrilled by the idea of a murder mystery, especially when Joffrey gave so many people so many reasons to off him.

Game Of Thrones airs Sunday nights on HBO.

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