Karen Pirie ending explained: Who killed Rosie Duff in the ITV crime drama?

The ultimate whodunnit has been solved

Lauren Lyle as DS Karen Pirie in Karen Pirie
(Image credit: ITV/Future)

Karen has solved the Rosie Duff cold case, but did anyone work it out before the big reveal?

The final episode of the excellent Karen Pirie has now aired, marking a sad goodbye to the first woman in television to rock a bum bag in at least three decades. Not only did DS Karen Pirie sport a strong look, she was also fierce, and gently flawed in the most relatable ways. She handled Rosie Duff’s case with grace and integrity, despite finding out she’d only been given the case to tick a few equality boxes. There were of course the multitudes of inevitable red herrings - some that Karen took on the nose, and some that left her screaming into an abyss - the audience right at her side. Now the 25-year-old cold case has been solved, exactly who was it that killed Rosie Duff? With enough twists and turns to make you dizzy, audiences could have missed who did it and why.

Riveted audiences have been asking in their droves, what is Karen Pirie based on? We have everything you need to know about the source material for the show. For anyone not quite yet caught up who wants to know how many episodes and where to watch Karen Pirie on catch up - we have the answers. Viewers searching for more crime drama to get their into, should watch ITV’s The Walk-In based on a horrifying true story, starring Stephen Graham.

Karen Pirie ending explained: Who killed Rosie Duff?

Rosie Duff was killed by DS Jimmy Lawson. He had been in a relationship with Rosie when she was 15 and he was 21, and she had become pregnant. Rosie had the baby secretly adopted, and Lawson became jealous when she wanted to move on from him into a different relationship.

Only those close to Rosie knew about the baby, and she told them the baby’s father was a friend of hers, to protect Lawson. She told everyone the baby had died, even telling Lawson the same. Once back in St Andrews and trying to rebuild her life, Lawson plagued Rosie to re-start the relationship, but she wanted to move on. 

Lawson then continually followed Rosie - often drinking in the bar where she worked - to try and prevent her dating anyone else. Rosie documented this in her diary with increasing frustration, but still didn’t name Lawson as her stalker. When Rosie began a relationship with Alex, she kept it shrouded in secrecy to avoid Lawson finding out. Alex believed she was ashamed of him because of his race, and Rosie wasn’t able to tell him the truth.  

When Rosie was walking home from a party alone, Lawson persuaded her to get into his car so they could chat. This was seen by eye witnesses, but had never been followed up - something Karen uncovered when reviewing the evidence. Lawson, temporarily living in a caravan, took Rosie there where he raped her. Once she told him to stop, he strangled her. Lawson had been painting the caravan with a special paint, which had gotten onto Rosie’s cardigan. He’d made sure Rosie’s clothing disappeared from the evidence room, but the cardigan had been mis-filed and Karen was able to match the paint to the caravan.   

To cover his actions, Lawson decided to make Rosie’s death look the same as another unsolved murder he’d heard about during his career- one with apparently religious or ritualistic motives. Cutting her across the stomach and leaving her strategically placed in the cathedral graveyard, a ritualistic murder was indeed the first line of inquiry for the police. Although Ziggy, Weird, and Alex looked guilty by being covered in Rosie’s blood and pictures being found of them with her at a party, they were really innocent. The boys were in the wrong place at the wrong time. They were secretive about their involvement with Rosie because they believed her murder would immediately be pinned on Alex, being black.

It also appears that Lawson killed DI Barney MacLennan, who wanted to follow up the eyewitness accounts pointing towards Lawson as the one seen bundling Rosie into a car. Therefore he didn’t drown the night Weird threw himself into the sea, but was likely murdered by Lawson - although Lawson didn’t fully admit to this. Lawson admitted to Karen once he was under arrest, that he gave her the job believing she’d never be able to solve the case. 

Rosie’s daughter Grace told Karen that although she’d been adopted, her upbringing hadn’t been a happy one. She felt anger that she’d never been given the chance to know her mother. When podcaster Bel Richmond gave away the identities of Ziggy, Alex, and Weird as potential suspects, an angry Grace mowed Ziggy down and killed him. She then attempted to kill Alex by shooting him, and kidnapped his newborn baby girl. Weird escaped an attempt on his life, when another suicide attempt put him in hospital, where Grace couldn’t get to him - although she had evidently been snooping around his house.  

Grace gave herself up to Karen, who let her witness Lawson being arrested in the hope it would offer her closure. Grace herself was then arrested, and she is last seen in prison. Her final moments are meeting Rosie’s brothers - and her biological uncles - Colin and Brian for the first time. They had no idea she existed, believing she died shortly after birth. Alex survived the shooting, and was reunited with his wife and daughter - his name now cleared. Weird also survived his suicide attempt and the two are seen at a memorial for Ziggy where they are both devastated at his loss, but relieved to be free of the case that’s haunted them their entire adult lives.

Lauren Lyle as DS Karen Pirie, Zach Wyatt as DS Phil Parhatka and Ariyon Bakare as Alex Snr. in Karen Pirie

(Image credit: ITV)

Is Rosie Duff real?

Rosie Duff isn’t a real person, but the series is based on real social issues faced by women in society today. Women continue to be murdered and feel unsafe when out alone. The show also highlights issues around race and the likelihood of people of colour being blamed for crimes committed.

Speaking to The Big Issue, Karen actress Lauren Lyle spoke about some of the issues highlighted and why. She said “It is such a relevant story, a reality of what’s happening. It is a fresh and necessary take because it’s not as though this is fiction. Women are continuing to be murdered. And until that stops happening, why would we stop highlighting it and putting it in the public eye? It’s important. Even having lots of characters of colour and having that nuance of what it means for them. What it’s like for them to be in the police in 2022”.

The series weighs in on how much hasn’t changed for women in 25 years, with locals at the time of Rosie’s murder being seen saying she shouldn’t have been out late and alone. Even reinvestigating the case in 2021, Karen points out that Rosie was penalised for having had a baby and been found to have had multiple sexual partners. While asserting that there’s nothing wrong with a woman wanting a sex life, Karen acknowledges this made Rosie less than the perfect victim - she thinks this could be part of the reason the public lost interest in the case.

Gemma McElhinney as PC Janice Hogg Jnr, John Lumsden as Ziggy Jnr, and Anna Russell-Martin as Rosie Duff in Karen Pirie UMSDEN as Ziggy Jnr.

(Image credit: ITV)

Who wrote Karen Pirie?

Val McDermid wrote the book Distant Echo, on which Karen Pirie is based. Actress and writer Emer Kenny wrote the screenplay and was responsible for adapting the novel for television.

McDermid has been vocal about her happiness at the novel being adapted for television, but didn’t want any part in the adaptation process. Speaking to The Guardian, she said “I want to write novels, not TV scripts”, adding that she particularly wanted to remain distant from the series, because the aim was for it to feel younger than other police shows. At 67-years-old, McDermid was happy to leave Kenny and Lyle to the creative side of turning her novel into a different creative outlet.

At 32-years-old, Kenny wrote and executive produced Karen Pirie. She also stars alongside Lyle as Karen’s best friend, River Wilde. She said “I was very aware of being a young showrunner. So I wanted to try to do something new with the mainstream ITV crime brand. My mantra was ‘cool and fresh’, which I said so often people were eye-rolling at me.” She added “I don’t think there’s any other police detective this young on TV”, although many exist in real life and she wanted to depict this - also with a woman in that role. 

What has Emer Kenny been in?

Emer Kenny is best known for her roles as Zsa Zsa Carter in Eastenders, and Penelope Windermere in Father Brown. She has also appeared in Pramface, The Duchess, and The Curse.

As a writer, she has written for Eastenders as well as acting in it, and also written for Doctors, Holby City, Red Rock, Harlots, and Save Me. She is married to television presenter Rick Edwards, and the couple currently have no children.

Kenny worked with The Walking Dead and Line of Duty actor Lennie James, on the series Save Me. She credits James with giving her the inspiration to make her mark in writing and forge ahead with becoming a showrunner. She told Radio Times “It's been such hard work. It's been a real mountain to climb for the past four years”. 

Speaking about being writer and executive producer for Karen Pirie, Kenny said “I also knew that it was really important for me to be across every single creative element right from the beginning, right to the end, because when you have that central voice, a show feels really cohesive and clear. I think that just feels more identifiable if it's through one person's view. I really wanted to be that for this show, so I was really in the weeds with this: with the casting, I was on set every single day, all the way up to the trailers and the poster. I've wanted to be across every single thing”.

Karen Pirie season 2: Everything we know so far

At the time of writing, Karen Pirie hasn’t been renewed for season 2. However, the drama has been hugely popular for ITV, and this could signal a greenlight for another series. Val McDermid also has plenty of material featuring the detective, for television adaption.

Fans on social media were coming out in droves to ask for a second season of the show. One fan wrote on Twitter “@MissEmerKenny

has done an absolute fantastic job on #karenpirie One of my favourite crime dramas in a long time! And @LlaurenLyle  has been fantastic as Karen Pirie. Crossing all my fingers & toes we get a series 2”

Another fan said “I have read all the #KarenPirie books from @valmcdermid and when a new adaption of books are made, sometimes they don't work....on this occasion they knocked it out of the park. Congratulations all round. Onto series 2 I hope”.

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Lucy Wigley
Parenting writer - contributing

Lucy is a mum-of-two, multi-award nominated writer and blogger with six years’ of experience writing about parenting, family life, and TV. Lucy has contributed content to PopSugar and moms.com. In the last three years, she has transformed her passion for streaming countless hours of television into specialising in entertainment writing. There is now nothing she loves more than watching the best shows on television and sharing why you - and your kids - should watch them.