I Know What What You Did Last Summer's Cast Revealed The Complicated Way They Tried To Figure Out The Show's Killer

With just two episodes left of I Know What You Did Last Summer to be revealed in the coming weeks, the question of who the vicious killer is in the series is high on our minds. Is it one of the members of the friend group seemingly racing against time to stay alive, a member of the small town we’ve overlooked, or a character creeping in the shadows we’ve yet to meet? The Amazon Prime horror series is serving as a high-stakes murder mystery for us as an audience, but apparently it was even more intense on the set. 

When CinemaBlend spoke to the I Know What You Did Last Summer cast of the remake, we learned that the stars were just as lost as we are as we binge our way through the show. The show’s lead, Nocturne’s Madison Iseman, who plays twins Allison and Lennon, shared her experience on IKWYDLS

We never knew how the series ended. We were only given the first four episodes when we all signed on. We started a bet from the beginning of who this killer is and I think everyone was wrong. I think there was maybe one person who got it right but from the beginning we were all trying to analyze and figure out, your person was here then, but then your character was there, but then they did this and we couldn’t figure it out. We literally couldn’t crack the code.

The series does a killer job of taking us through misdirects. As I told the cast, I found myself suspicious of each of their characters as I went from episode to episode. Ashley Moore plays Riley, the matter-of-fact drug dealer who fell into some serious danger in this week’s episode. Don’t worry, no spoilers here if you haven’t caught up! Moore said this: 

It was exciting for me. It kept you on your toes and especially with us not knowing who the killer was until the very end, we were all like ‘who is it, who is it?’ That was really fun.

Ezekiel Goodman plays Dylan and has an especially complicated story, considering he was in love with Allison, the teen whose death started it all. Goodman apparently had no idea who the killer was either while on the set of the series, but really enjoyed that aspect of it as an actor. As Goodman shared: 

I think it makes it so much more exciting and honestly easier to inhabit the characters’ world when you don’t know everything they don’t know, right? I got to go on the ride with my character which was really special.

Based on what the cast told us, nobody knew how the season would end until it was absolutely necessary to film the sequences to come in the remaining episodes. Brianna Tju, who plays the fabulous but bruised Margot in the show, said that along with making bets they were also doing mental acrobatics on set to find out for themselves if one among them was the culprit. In Tju’s words: 

We were constantly curious. It’s a murder mystery on screen and off screen because none of us were told who the killer is for a long time honestly, I think until we were shooting the sixth episode. I remember Ashley and I would have these mental venn diagrams of who it would be and why and trying to put the pieces together of the timeline and story arc and all these things. And to be honest, our minds changed constantly. We would be so sure it was one person and then the next day it would be someone else and to be honest, Sarah, our showrunner, did an amazing job of confusing people, so it makes it very interesting to watch.

And based on Sebastian Amoruso’s words, who plays Margot’s best friend Johnny, when they did eventually find out who it is, it was thankfully rewarding. That’s what makes a show like this work, but we’ll have to see once the show plays out. As Amoruso said: 

And I also think the payoff is there too. It’s not random, it’s well thought out and I think when you watch it with retrospect, it’s maybe even better.

I’m sure you have your own theories. The sixth episode of IKWYDLS is streaming on Amazon Prime now with two more episodes to go in the next two Fridays.  

Sarah El-Mahmoud
Staff Writer

Sarah El-Mahmoud has been with CinemaBlend since 2018 after graduating from Cal State Fullerton with a degree in Journalism. In college, she was the Managing Editor of the award-winning college paper, The Daily Titan, where she specialized in writing/editing long-form features, profiles and arts & entertainment coverage, including her first run-in with movie reporting, with a phone interview with Guillermo del Toro for Best Picture winner, The Shape of Water. Now she's into covering YA television and movies, and plenty of horror. Word webslinger. All her writing should be read in Sarah Connor’s Terminator 2 voice over.