Long Bright River ending explained: Who was the killer?

The Amanda Seyfried drama focuses on Mickey, a Philadelphia cop who is determined to protect the area that she's grown up in.

But when a string of murders of local sex workers takes over the city, Mickey starts to realise that the case is a lot closer to home than she first realised.

Across the eight episodes, Mickey is also reckoning with the disappearance of her sister Kacey, who is struggling with opioid addiction.

Speaking of the note she wanted to leave the series on, showrunner and executive producer Nikki Toscano told TheWrap: "Though loving people that suffer from addiction can be very heartbreaking, because you’re constantly wondering when the other shoe is going to drop, I think what we come to realise at the end, and what we wanted you to leave with, was the hope that the these two sisters and their love for each other can transcend the hooks, the poverty, the addiction that have tried to pull them back down."

But who was the killer that Mickey had been looking for? Read on for a full breakdown of the Long Bright River finale.

Long Bright River ending explained: Who was the killer?

Working together to try and figure out who the killer was, Kacey had initially told Mickey that the murderer was none other than her previous policing partner Truman, with whom Mickey had struck up a romantic relationship with eventually as well.

Things seemed to be going well for the pair up until this point, but it was clear that Truman was hiding his own secrets from Mickey. Was he the killer, though? No.

It turns out that Kacey hadn't known Truman had taken a leave of absence and was only told that the killer was Mickey's partner. So, Kacey believed that the killer was Truman, not realising that Mickey had a more recent policing partner: Eddie Lafferty (Dash Mihok).

Mickey had previously asked to work by herself and without Eddie after thinking that he wasn't respecting the female victims at the heart of the case.

Mickey shows Kacey a picture of Lafferty and she confirms that he is the killer.

It's understood that Lafferty was using his police badge in order to get sexual favours from Kensington sex workers like Amelia, Taylor and Elizabeth. Threatening to expose him to his boss, Lafferty's motivations turned deadly.

When confronting him in an abandoned church, Lafferty tells Mickey that he killed the women because "things got out of hand". Although Mickey thinks she's there alone with Lafferty, what she doesn't realise is that Kacey and several of her friends from The Avenue are hiding out and ready to attack.

Seeking justice for their friends' murders, they shoot and kill Lafferty, with Mickey taking the final shot and demonstrating that she is on these women's side after all.

Speaking of that moment, Toscano told TheWrap: "It’s about the empowerment of these women – these women that have been largely discounted and dismissed in society – and giving them a voice.

"I think the power of that moment is to allow them to have that voice and to have that win, even if it meant compromising [Mickey’s] own place on the force, her place in society. It was worth it in the end for her."

Mickey also resigns from the police. With Lafferty having worked under his high school friend Sergeant Ahearn (Patch Darragh) and having clearly been protected, Ahearn maintains his denial of any involvement in covering up Lafferty's crimes.

It all signalled that corruption in the force was worse than Mickey could've imagined, and that no matter how hard she tried, the wrong people continued to be protected.

What happened between Mickey and Truman?

After Kacey's intel, Mickey doesn't quite believe that it could be Truman who is committing these murders. It turns out that her gut feeling was right – but that's not before she makes an irreversible mistake.

Following Truman, Mickey sees him injecting an unconscious girl at a local drug house. It turns out that Truman was injecting her with naloxone in order to save her life, not insulin as the killer had been using.

Mickey pulls a gun on Truman, with the damage to their relationship already done.

He had been helping a friend in their neighbourhood watch for the most at-risk people, but Mickey's actions were too much for him to forgive and, sadly, that level of mistrust was enough for Truman, and the pair don't end up together despite admitting their love for one another.

What happened to Kacey?

Having been instrumental in figuring out who the killer was and ultimately having a major hand in ending Lafferty's life, things actually turn out quite well for Kacey.

Having been sober and found refuge at her father's (who they believed was actually dead), Kacey surprises Mickey by turning up pregnant. Although Kacey's disappearance was part of the motivation for Mickey getting so involved in the murder investigation, Kacey has always been alive and well.

In a twist, we learn that Thomas isn't actually Mickey's son and was Kacey's first child, a product of Simon having exploited her vulnerability in the midst of her addiction as a teenager. With Thomas having been born in opioid withdrawal, Mickey made the decision to take him away from Kacey and strive to give him a better life.

Ultimately, Mickey chose Simon over her sister at the time, but realising her mistake and the fact that she had been groomed by Simon herself from the age of 14, Mickey apologises to Kacey and the pair begin to reconcile.

Kacey eventually gives birth to a healthy baby and it marks a new leaf for the sisters, with the final moments of the episode showing them enjoying life together with Thomas, Gee and the new baby.

Long Bright River is available to stream as a box set on Channel 4 on Sunday 11th May and will air on Sunday 18th May at 10pm.

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