Who was the killer on I Know What You Did Last Summer Season 1?

I Know What You Did Last Summer Season 1 gave us a twisty season filled with blood and gore. Who was responsible for it all?

Caution: There are spoilers for the I Know What You Did Last Summer Season 1 finale in this post.

We knew we’d get answers at the end of I Know What You Did Last Summer Season 1. We’d find out the identity of the killer. The question was whether we’d guessed right.

One thing that we knew had to be the case was that it was one of the friends. After all, too many secrets were known.  So, who was doing all the killings and was it because of the accident or due to something else?

I Know What You Did Last Summer Season 1 killer revealed

It turned out that one of the group was behind it, but it wasn’t Dylan. It was Margot all along.

When you watch the series, this reveal probably isn’t all that surprising. Margot was very quick to push the blame on everyone else.

She wasn’t alone, though. At first, she did act alone. She’d stolen Allison’s phone in the caves, and Johnny knew about it. When Johnny started blackmailing her, she decided to kill him. Kyle, her mother’s hired security, found out. Instead of turning Margot in, Kyle decided to start helping Margot. He even pushed her out of the window that night.

Why did Margot do it? It wasn’t to actually out the group about Allison’s murder. It was to get the truth from Lennon. Well, Allison. She suspected that Lennon was actually Allison and she wanted Allison to own up to it.

In the end, she didn’t get the confession. Allison continued to pretend to be Lennon, and shared that she felt loved by Margot the night that the twin was killed.

Margot had already thought everything through, as well. When she stabbed Allison, the knife had Dylan’s DNA all over it. Dylan was framed for everything. Even Allison lied for Margot, so the two get to enjoy a life together. Margot and Kyle get away with everything they did.

There are a lot of storylines to cover if I Know What You Did Last Summer is renewed.

What did you think of I Know What You Did Last Summer‘s ending? Did you guess who the killer was? Share your thoughts in the comments below.

I Know What You Did Last Summer is available to stream on Amazon Prime Video.