But You Can’t Prove It, also known as James Doakes Reaction Images, refers to a series of image caption memes using reaction images of Dexter character James Doakes (played by actor Erik King) with determined looks on his face, including an image of him driving a car and an image of him holding a drink in a bar. The memes feature captions about knowing that someone is hiding a secret from you, but you can’t prove it, a reference to Doakes, who believes Dexter Morgan is a serial killer but is unable to prove it. The format was popularized online throughout 2025 on sites like TikTok and X / Twitter, first appearing online as early as September 2024 on Reddit.