A Good Girl's Guide to Murder ending explained: Who killed Andie Bell?

A Good Girl's Guide to Murder, adapted from Holly Jackson's bestseller novel series of the same name, is a thrilling ride from start to finish. Premiering on August 1, 2024, and having made its way to BBC Three, BBC iPlayer and Netflix, the series comes with a gripping plot refreshed for TV.

A Good Girl's Guide to Murder follows Pip Fitz-Amobi, a high school girl who takes on a very challenging senior project: the reopening of Andie Bell's murder case that was closed with a suspect already convicted. While Pip delves deeper into the case, secrets begin to surface, and she starts to think that the truth might just be way more shocking than anyone ever thought it to be.

It builds in tension, leaving viewers on tenterhooks as the finale episode of A Good Girl's Guide to Murder unfolds with many kinks and twists. The climax is when an astounding truth is revealed: Andie Bell's murder wasn't a random crime at all but committed by someone close. The big reveal is that Becca Bell, Andie's sister, was behind Andie's death.

That revelation shocks Pip to his core but also turns the entire investigation on its head, much in keeping with the series' themes of hidden agendas and family dynamics.

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Who killed Andie Bell in A Good Girl's Guide to Murder?

Andie Bell was murdered by her little sister, Becca. The tragedy happened when the two sisters quarrelled.

During the fight, Andie hit her head on something, which rendered her incapable of fighting further. Becca was in shock when Andie hit her head and started choking. Instead, she watched as Andie died without help.

Realizing the situation she had put herself in, Becca decided to cover up the incident. She dragged Andie's body and placed it in her car before driving off to one of their family's older homes. She hid Andie's body inside a septic tank in the property.

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Why did Becca kill Andie in A Good Girl's Guide to Murder?

Becca hadn't intended to kill Andie. It was a terrible end to an argument between the two sisters that went too far.

Becca had been influenced profoundly by a shocking incident involving Max Hastings, who had drugged her using Rohypnol, a drug supplied by Andie and against whom Becca wanted to file a rape case.

She was scared that Becca's report might expose her drug dealing activities and attract severe consequences for her. The climax of the alteration was Andie's selfish act of not wanting to help in bringing justice to her sister.

The argument escalated into a fight that led to the accidental death of Andie. During the argument, emotions ran high. It was in that heated moment that Andie hit her head and began choking on her vomit.

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What happened after Pip found out the truth in A Good Girl's Guide to Murder?

Things started going haywire after Becca confessed the truth to Pip about Andie's death. Desperate and flustered, Becca resolves to silence Pip to bury the truth once and for all.

Becca drugged Pip with Rohypnol, just like Max Hastings had done. Becca overdosed Pip with the drug and tried to throw her in the same tank where she hid Andie's body.

Fortunately, Ravi was back in town and was looking for her. Cara, Pip's childhood best friend, had access to her location through GPS. Cara and Ravi arrived in time at the location and saved her. They found Pip struggling to fight off Becca. The police arrived in time and arrested Becca.

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Towards the end of the finale episode of A Good Girl's Guide to Murder, Pip, armed with all the evidence she had gathered, confronted Max Hastings. She's resolved to bring him to justice for all his wrong deeds, including the rape of Becca Bell.