Karen Pirie ending explained: Who killed Rosie Duff?

It turns out the murderer was none other than DS Jimmy Lawson, the one who put Karen on the case in the first place!

In the 1990s, he had had a relationship with Rosie when she was aged 15 and he was 21. As she was underage and he was a police officer, she went away for a summer and had the baby in secret, later coming back and telling both Lawson and her family it had died.

Of course we know this wasn't the case, and Grace was in fact alive and well. But when Rosie had returned to St Andrews, Lawson had wanted to pick up where they had left off - something she definitely didn't want.

He had then followed her for three years, drinking in the bar where she worked and making sure she didn't date anyone else. However, when she did start moving on with Alex, he'd left the pub to look for her and had picked her up off the side of the street as she walked home in the rain.

He had taken her up to his caravan, something Karen knew because of the rare paint found on her cardigan. Once there, it appears that Lawson raped her and when she told him to stop, he had strangled her until she was unconscious. He believed her to be dead at this point and decided to make sure it looked like it wasn't him.

He took action, deciding to make her death look like another unsolved murder he'd come across in his career. He took her to the cathedral, laid her out on a grave and cut her across the stomach, at which point she died.

He had then cleaned himself up and got back to the crime scene within 45 minutes, relieved that Alex, Ziggy and Weird had found her so he could pin it on them.

He had then corrupted the case from the inside, making a box of evidence go missing - but hadn't accounted for the human error of her cardigan being genuinely misfiled.

There's also a suggestion he may have killed DI Barney MacLennan, who knew about an eyewitness who had seen her getting in his car, although he claimed it was an accident.

Lawson as good as confessed at the end of his interrogation with Karen, admitting that he underestimated her and that's why he gave her the job.

What happened to Grace at the end?

Grace's story was perhaps the most tragic of all throughout the series, as her mother's death cast a shadow over her life and eventually led to her kill an innocent man, Ziggy.

She admitted that she had originally just wanted to see the men who killed her, but had become enraged when she saw their happy lives as wealthy, successful individuals. She wanted answers and she wanted justice.

She had shot Alex and taken his new baby, which led to an eventual standoff with Karen. She finally gave herself up when Karen promised her justice, which she delivered with the arrest of Lawson. Grace was then arrested for Ziggy's murder as well as the attempted murder of Alex and the abduction of his baby.

While in prison, she had finally got to meet her two uncles, Colin and Brian, as they visited her in a tearful meeting in what DI Lees noted was a "bittersweet" end to the whole affair.

What happened to Alex and Tom?

Alex and Tom reunited at a memorial for Ziggy, with the latter having survived his overdose and the former having also survived being shot and now reunited his wife and baby.

The pair hugged and cried together, having finally been exonerated fully but having lost their friend.

How were things left with Karen and her friends?

In the end, Karen and her friends were left in a good place. Karen was told by DI Lees that she was a credit to the service, after which she went to join Phil, Jason and River at the pub.

After some laughs together, Karen and Phil went off arm in arm, with all seemingly set right as the credits rolled.

All episodes of Karen Pirie are available now on ITV Hub. You can also get a 30-day free trial of ITV Hub+ on Amazon Prime Video.

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