Warning: Spoilers ahead
Fans of Netflix crime series Stay Close think they have cracked a code that might allow viewers to spot bad characters from the offset.
The theory, shared in a subreddit thread, has began to garner attention as more viewers agree that some of the cast's outfits appeared to play a key role in the series.
In the final episode, nightclub owner Lorraine was revealed as the murderer behind the serial killings in a shocking plot twist.
Yet for some, it was clear she had been a sinister character all along. The clue to her heinous crimes was in her outfits and her favourite colour to wear. Lorraine wore purple in nearly every scene, which some fans think marked her out as the murderer or the 'bad' character in the series.
One user on Reddit pointed out their theory, before others agreed they had spotted it too.
The eagle-eyed viewer wrote: "This is just an observation I made and I'm here looking to see if anyone else noticed it. The character of Lorraine seemed to wear the same colours in a lot of her scenes - yellow and purple.
"It became a mild thing for me - each new scene she'd be in, I'd want the camera to pull out to see the entire outfit. Often enough, it would be purple and yellow.
"Anyone else notice this? I know Broome didn't because he didn't notice much."
Another fan explained the colour theory further, likening it to other series including Breaking Bad and Better Call saul which apparently used the same device. They commented: "My GF picked up on the Purple as well. My theory is similar to the colors of Breaking Bad/Better Call Saul - Broome wore Blue, like Kim Wexler and Skyler White, because he was a detective and represented the law.
"Red represents the criminal world/murder. If you mix red and blue colors, you get purple. She was kinda of like Marie in BB who always wore Purple because she was caught between two worlds, her husband Hank who was a part of the law and her sister Skyler, apart of a criminal family.
"Lorraine was caught between two worlds, her criminal world or murdering men, and her love for Broome, the detective. Purple was a clue to her being the killer. At least that is my theory."
We reached out to Netflix for comment.