Murder Most Puzzling, the Channel 5 series based on the best-selling novels by Parnell Hall, continues this week with episode 2 – and some new faces in the guest cast.

It’s a celebratory episode at first as it’s Cora’s birthday. However, she’s feeling bored and fed up… It’s been too quiet since she helped catch The Graveyard Killer and she’s itching for another mystery to solve…

So imagine how thrilled she is when Becky hires her to investigate a case… Becky asks Cora to dig into the case of convicted killer Darren Duggan. Is he really innocent, as his girlfriend Stacey seems to think?

At Bakerbury Prison, Cora interviews the rather unlikeable Darren who, five years ago, was found guilty of murdering his ex-girlfriend Anita. He insists he didn’t do it and points the finger at local ‘weirdo’, Roy Gleeson…

Here’s everything you need to know about the guest cast list of Murder Most Puzzling episode 2.

Aidan McArdle guest stars as Governor Peacock in Murder Most Puzzling episode 2 [Credit: Channel 5]

Murder Most Puzzling episode 2 guest cast: Aidan McArdle guest stars as Governor Peacock

Dublin-born actor Aidan McArdle, 54, portrays Governor Peacock in the guest cast of Murder Most Puzzling episode 2. In the latest instalment of the cosy crime series, Peacock is the prison boss, who warns Cora off the investigation… He obviously didn’t get the memo about Cora being particularly untameable!

Aidan has been on our screens for more than two decades, ever since he popped up as James O’Hearne in a 2002 episode of Casualty. Since then, he’s appeared in dozens of TV shows including All About George, Jane Eyre, No Angels, and Secret Diary of a Call Girl.

In 2008, he appeared as Andy Doonan in Beautiful People, which was his biggest role at that time. The series followed the flamboyant and ambitious 14-year-old Simon Doonan, who had dreams that stretched beyond his hometown of Reading.

A year later, Aidan – who is Steve Coogan’s cousin – played Silvester in the period drama Garrow’s Law, the true tale of London’s Old Bailey counsel William Garrow.

Between 2014 and 2015, Aidan once again nabbed a great role in the cast of Mr Selfridge. He played Lord Loxley in the ITV drama. Lord Loxley was the abusive ex-husband of Lady Mae Loxley and a primary antagonist in the second and third series.

Other notable roles include John Docherty in The Mill, Desmond Rane in Clean Break, Healy in The Fall, and Roger Hollis in The Trial of Christine Keeler.

In the past year, Aidan has been particularly prolific! In 2024, he played Charlie Reid in Blackshore, Michael Flannery in Ridley, Patrick Norris in Showtrial, and Aidan Truther in MDRJago. This year, he has already portrayed Pete Benedict in the Bergerac reboot, and Chief Inspector Whitlock in Sherlock & Daughter.

Actor Ash Rizi plays Dean Boyle in Murder Most Puzzling [Credit: C5]

Ash Rizi plays Dean Boyle

Northern Irish actor Ash Rizi portrays former convict-turned-bartender Dean Boyle in Murder Most Puzzling episode 2. Eagle-eyed viewers will have noticed that many of the cast are Irish or Northern Irish. This is because the show was filmed in Belfast.

Ash, who is of Persian descent, is perhaps best known for portraying Darius Kazemi in several episodes EastEnders. Or perhaps Nathan in the graduate comedy Drifters.

Just this year, he starred as Dr Amit Shafi in the medical drama Malpractice. Other notable roles include Vercta in one episode of The Witcher, Riz in Everything I Know About Love, and Dr Sebastian James in Hope Street. He’s also appeared in Unforgotten, Luther, Silent Witness, and Doctors.

It’s Cora’s birthday in the latest instalment of Murder Most Puzzling [Credit: Channel 5]

Full guest cast list of Murder Most Puzzling episode 2:

First of all, Aidan McArdle stars as Governor Peacock.

Ash Rizi plays Dean Boyle.

Newcomer Aidan Gallagher – not to be confused with the Umbrella Academy star of the same name – plays the DCI Hooper Lookalike.

Constance Baird, in her first TV role, stars as Cora’s imaginary granddaughter.

Newcomer Tabitha Smyth plays Stacey Gallivan.

Wind and Bone’s Matthew Sharpe portrays Darren Duggan

Trivia’s Sarah Gallagher stars as Ida Blunkett/Bella Dryver.

Faolan Morgan portrays Roy Gleeson.

Tony Devlin plays LIN PI Burns.

Charis Agbonlahor stars as Margot Snell.

Warren McCook portrays the dance instructor.

Lastly, Odhran McNulty plays Stefan.

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Aidan McArdle stars as Governor Peacock in the guest cast list of Murder Most Puzzling episode 2 on Thursday, June 26, 2025 at 8pm on Channel 5.