Last January - when Netflix viewers across the world were gripped by Making a Murderer - Steven Avery hired a new defence lawyer by the name of Kathleen Zellner, and she's hell bent on getting her client exonerated. Last night, the below tweet was posted from the show's official account.

So what is luminol testing? According to the Bureau of Criminal Apprehension: "Scientists can take advantage of the luminol reaction to locate potential blood evidence that would be undetectable through visual examination. The light, or luminescence, emitted in the luminol reaction is thought to result when an oxidizing agent, such as blood, catalyzes the oxidation of luminol by hydrogen peroxide in a basic solution."

Illinois-based attorney Zellner - who "specialises in reversing wrongful convictions" - released the following statement via The Wrap: “We are continuing to examine every aspect of Mr. Avery’s case and all of his legal options. We are confident Mr. Avery’s conviction will be vacated when we present the new evidence and results of our work to the appropriate court.”