Orange Is The New Black has been providing flashbacks to the characters' pre-Litchfield lives since Season 1, explaining what went wrong that brought these women to prison. From offenses small (possessing marijuana) to major (murder), the reason for almost every prisoner's incarceration has been explored with one major omission. Red has been a major cast member since the very beginning of the series, and the show has hinted that she's had some criminal involvement in the past but the show has yet to reveal why Red is in prison on Orange is the New Black.
Red's criminal activities involved taking a major role in her husband's crime ring in America, smuggling illegal goods, and providing business advice to her husband's boss. Even if she wasn't actively running the crime ring, she was still aware of it and participating enough that she would reasonably be thrown in jail should things have gone south. However, the show has been hesitant to reveal just how badly things go for Red. This isn't atypical of the show, which often draws out backstories slowly and through implications of what has gone wrong, but the longer Red's story goes on the more it looks like she could've gotten herself into some especially deep trouble. At this point, the best-case scenario is she's only been arrested for conspiracy, but a ground-breaking discovery in her freezer indicates she may be capable of some genuinely evil acts. Season 5 of OITNB could finally show audiences what really went down, and chances are it'll force fans to look at Red in a whole different light.
In Season 4 it was revealed that when Red's freezer was searched, police found five dead bodies stored there. It's implied that this discovery helped put Red, then known as Galina, in jail, but the specifics are never explained and the ambiguity leaves a lot of room for possible versions of the truth. Was Red merely hiding the bodies of murder victims at the whim of her crime bosses? If so, wouldn't have she been able to claim that she was being threatened and forced into doing so?
Another possibility is that she wasn't merely storing the bodies there until a proper disposal method arose — it's entirely possible that Red is the reason those bodies were dead in the first place. Red grows increasingly competent as a criminal as she rises up the criminal ranks, and she may have had to take a few people out to keep her standing within the crime ring. If Red is in jail for murdering five people, however, it seems a little too convenient that she's in Litchfield as opposed to a supermax facility or somewhere else where she would be far more restricted in her freedom.
That's the unique thing about Litchfield, and by extension Orange Is The New Black. The show redefines the standard TV definition of "criminal" to show that now everyone who gets thrown in jail is a heartless murderer. More often than not, someone ends up in Litchfield not because they did something evil, but simply because they messed up. Red surely did something bad, but likely didn't do anything awful — or if she did do something awful, perhaps it was the result of an accident. In the end, it doesn't really matter how Red ended up in Litchfield, the only thing that matters is that she is there and, like a professional cook with sub-par ingredients, will have to make the best of a sour situation.