Riz Ahmed as Naz in The Night Of. Photo: HBO

Last night, the eight-episode HBO crime procedural The Night Of officially reached its halfway point. Yet it appears we’re no closer to knowing who actually killed Andrea Cornish than John Turturro’s John Stone is to curing his eczema-afflicted feet.

Confirming that Naz (Riz Ahmed) did not murder Andrea, the enigmatic young woman with whom he spent a life-altering, drug-hazy evening, is only part of what this limited series is about. But as The Night Of continues to peer into various dysfunctional corners of America’s flawed judicial system, certainly the key question it must address is this: If Naz, who discovered Andrea’s stabbed, lifeless body but doesn’t remember killing her, is not responsible for her death, then who is?

The impatient may be inclined to seek answers to that question from an outside source: Criminal Justice, the five-part 2008 BBC series that inspired The Night Of and can be viewed in full on Hulu. Watching it in tandem with the HBO drama reveals the many ways that The Night Of creators, Richard Price and Steven Zaillian, expanded on and added further nuance to its narrative. But given the similarities between the two plots, the British original may also provide some hints about how the murder mystery in the American version will be resolved. (Note: some major Criminal Justice spoilers will follow.)

The crimes at the heart of both shows unfold in pretty much the same way: A college-aged man borrows the cab normally driven by his father and unwittingly picks up a female passenger. She asks to go to the nearest beach, so the man — Ben, played by Ben Whishaw, in the BBC version, Naz in the U.S. adaptation — obliges. They hang out, then head back to her place, where they take drugs, drink, play a semi-bloody game of Five Finger Fillet, then have sex, at which point, Ben/Naz returns to the kitchen and passes out at the table. When he awakens, he goes back upstairs to retrieve his things and say good-bye to his companion, named Melanie in the BBC iteration, at which point he discovers she’s been stabbed to death. He panics and flees the scene in the taxi, committing a traffic violation that results in his being pulled over by police and, eventually, arrested in connection with the murder.

In both cases, the alleged perpetrator — an asthma sufferer who uses an inhaler at the scene of the crime — seems more like a victim of horrifying circumstance than a killer. Of course, we don’t know that for a fact. But in Criminal Justice, it is much easier to take that as fact because of the way Ben is portrayed. As played by Whishaw, he’s a lanky, jittery, emotional kid who is completely undone by the crime and his time in prison, a jail that’s unpleasant but still less gritty and intimidating than the Rikers Island shown to us in The Night Of.

There are certainly hints that Ben may not be the pure innocent he seems to be; we eventually learn that he’s been dishonest with his parents about dropping out of university. It’s also implied that, as a boy, he may have lied to his mom about his involvement in the death of the family cat, which, in contrast with The Night Of, counts as the only moment that a feline plays a significant role in the series. But Ben breaks down so many times post-arrest that, even in an altered state, it’s hard to imagine a guy this fragile committing such an atrocious act of violence. Another detail that’s worth mentioning: The crime in The Night Of is depicted in a much more grisly manner than the one in Criminal Justice, which takes the form of a stab wound to the chest and involves a hell of a lot less blood sprayed all over the walls. That difference certainly speaks to American premium cable’s tendency toward gratuitous, sexualized violence. But the brutality of The Night Of murder also implies that it would be tough for Naz to be guilty of committing it without remembering any of the details.

Criminal Justice is certainly interested in shining a light on the corruption and unethical behavior that compromises everyone in the British judicial process, from sleazy solicitor Ralph Stone (Con O’Neill), who, for the record, does have eczema on his feet, although the show doesn’t make nearly as much of it as The Night Of does, to detectives like Harry Box (Bill Paterson), who compromise the rights of the accused while seemingly acting with kindness. But this mini-series is much more focused on Ben’s experience than anyone else’s. Glimpses into the private lives of the various people involved tangentially in what’s happening, from Ben’s parents to the barristers trying the case, are rare and brief. With only five episodes in which to tell a complicated legal story, the canvas of Criminal Justice is much more contained and its desire to solicit empathy for Ben is much more clear. BIG SPOILER HERE, SO LOOK AWAY IF YOU DON’T WANT TO KNOW. When the verdict in the case and the identity of the murderer are revealed in the final episode — Ben is found guilty by a jury, but later exonerated when another man is revealed as the killer — it comes out in such a swift dump of information that the viewer is still left with a lot of questions about the specifics of what happened to Melanie the night she died. At least in terms of approach, I doubt The Night Of will conclude in a similar fashion. Specificity has been such a hallmark of the show — seriously, did you ever think you would learn this much about dealing with eczema from a Sunday-night HBO scripted series? — that I fully expect Price, Zaillian, and the rest of the creators to explain things more fully.

I also am convinced that our initial suspicions about Naz will be confirmed: He didn’t do it. In that very first episode, The Night Of shows us what happened from Naz’s perspective. Ever since, just like an attorney, it’s been trying to introduce reasonable doubt.

Like Ben, Naz has shown fear and feelings of panic since he’s been accused. But Riz Ahmed — with those deeply set, deliberately unreadable eyes of his — imbues Naz with a reserve of strength and an ambiguity that make him much more of a gray character than Ben was in Criminal Justice. In last night’s episode, we can already start to see how prison life is forcing Naz to reveal a backbone and, possibly, a dark side. The more he fits in with the inmates, the more Naz starts to seem like someone who might actually belong in jail, an idea conveyed by his now former attorney, Alison Crowe, when she tells a judge, “If we instead would like to see a young man with no criminal record turned into a criminal, then let’s have him sit at Rikers as long as the slow wheels of justice take.” Again: We have never seen Naz commit a crime. But The Night Of is painstakingly creating a picture of him that fits the criminal profile, which makes it easier to think maybe he really did commit murder.

While The Night Of most often invites us to have sympathy for Naz, it also encourages us to understand those responsible for putting him behind bars, to a much greater extent than Criminal Justice does. In the British series, for example, Box is much more of a stock character, the typical blunt arrogant cop who shouldn’t be questioned. As played by Bill Camp in the HBO series, though, he’s harder to pin down. He’s stubborn, yes, and a little arrogant, but the kindness he displays seems much more genuine. That, too, introduces reasonable doubt: If you think the guy accusing Naz is a decent man, you’re more likely to doubt Naz’s innocence even though that first episode should have told you all you need to know.

But the most intriguing difference between Criminal Justice and The Night Of is the fact that Naz is a Pakistani-American. Race was an issue in Criminal Justice: Ben, a white man, is accused of killing a black woman. But in The Night Of, it’s an issue that colors all preconceived notions about the accused. As the news over the last couple of days has once again sadly emphasized, Islamic-Americans are often viewed in this country with a contemptible level of skepticism and hate. By making the accused the son of Pakistani immigrants, Zaillian and Price are essentially forcing the audience to confront their own prejudice and decide whether they can look at Naz the same way they would look at a young man like Ben if he were in this same situation. Because even though he may not be as easily shaken as Ben, Naz is, in many other ways, a young man just like Ben.

That’s another reason why I think Naz didn’t kill Andrea; to give the show, and television in general, such a prominent Pakistani-American character and then reveal him to be a murderer would be extremely disappointing. I would be surprised if Zaillian and Price do that. The Night Of isn’t a show about shocking plot twists (he really was the killer all along!), it’s a drama about how systems of all kinds — legal, education, medical — fail people. The scariest thing about this series, which is also the scariest thing about Criminal Justice, may not be that an innocent man can be accused of murder, but that an innocent person with great promise can easily turn into something else when society forces him into its darkest, least forgiving corners.