Dark Heart

A True Story of Sex, Manipulation, and Murder

By: Rebecca Lavoie, Kevin Flynn

Narrated by: Paul Costanzo

Length: 9 hrs and 4 mins

Publisher's summary

Was murder part of the game?

Seventeen-year-old Kat McDonough grew up with theater in her blood - and a penchant for make-believe. More than a decade older, Seth Mazzaglia was well-known in the community theater circle of Portsmouth, New Hampshire. He, too, had a rich inner life - and he soon had Kat convinced that they were soul mates.

To intensify their bond, Seth lured Kat into a world of violent sex and role-playing, where she was his slave. But even that wasn't enough to satisfy his ravenous appetites. Enter Lizzi Marriott, the new girl in town. And when she accepts an invitation to Kat and Seth's apartment, she will never be seen again....

©2016 Kevin Flynn and Rebecca Lavoie (P)2017 Tantor

Critic reviews

"This book does much more than tell a crime story; Flynn and Lavoie gift the reader with an inside look at human frailty and the ways that a skilled sociopath can manipulate others toward the desires of their dark hearts." (Anthony Flacco, New York Times best-selling author of Impossible Odds)

Excellent new true crime material

This was my first time reading these authors, and I have to say I was very pleasantly surprised by Dark Heart. Like many others, I was already somewhat familiar with the case. I'm a huge 'audi-holic' and an even bigger true crime fan, so I really enjoyed the way the narrative was presented in a thorough, but concise manner. The authors did an excellent job balancing the razor-sharp line between focusing on the defendants, while not losing sight of the victim's story.

The narration was very smooth and comfortable to listen to. I only gave 4 stars here because there are some narrators out there that earn the 5th star imo. Nevertheless I like Paul Costanzo, and hope to hear more from him.

Overall I give Dark Heart 5 stars because there are a shortage of great new true crime books in print and audio formats such as this, and this story was well told and it's clear that the authors did their research. Despite the fact that they were not able to obtain more participation from Lizzy's family, they made an effort to give them a voice. It give us a glimpse into her horrific final moments as well as the dark and twisted world of Cat and Seth. If you enjoy a solid true crime story with suspense, real emotion, and a bit of the bizarre then you will enjoy Dark Heart. I look forward to more titles from these two!

I WISH this audio book was given to me for free in return for an honest review! 

Excellent mystery with lots of twists and turns

Enthusiastic thumbs up!! Such a tragic murder, so sorry to Lizzi's family. I wish we learned more about the victim, but I also found Kat's story fascinating. I really appreciated Rebecca and Kevin's structure and story telling. Didn't know anything about the case, so I was surprised throughout. Narrator is fantastic

Small Towns are not immune to senseless crime!

A case where mental illness is not a factor, but rather the cold,. cruel and selfishness of two lovers desire to take a life for no reason. May they be punished everyday for the rest of their miserable lives!

Great New True Crime... Finally!

This was my first time reading these authors, and I have to say I was very pleasantly surprised by Dark Heart. Like many others, I was already somewhat familiar with the case. I'm a huge 'audi-holic' and an even bigger true crime fan, so I really enjoyed the way the narrative was presented in a thorough, but concise manner. The authors did an excellent job balancing the razor-sharp line between focusing on the defendants, while not losing sight of the victim's story.

The narration was very smooth and comfortable to listen to. I only gave 4 stars here because there are some narrators out there that earn the 5th star imo. Nevertheless I like Paul Costanzo, and hope to hear more from him.

Overall I give Dark Heart 5 stars because there are a shortage of great new true crime books in print and audio formats such as this, and this story was well told and it's clear that the authors did their research. Despite the fact that they were not able to obtain more participation from Lizzy's family, they made an effort to give them a voice. It give us a glimpse into her horrific final moments as well as the dark and twisted world of Cat and Seth. If you enjoy a solid true crime story with suspense, real emotion, and a bit of the bizarre then you will enjoy Dark Heart. I look forward to more titles from these two!

I WISH this audio book was given to me for free in return for am honest review! Where do I sign up :p

This was decent

I prefer my true crime to be verbatim quotes that are told from interrogation rooms and court transcripts rather then summary after summary of the events which can leave room for Misinterpretation. But in whole, it was not terrible.

Great, but not safe for work!

I really enjoyed this book. The character development was excellent and I actually wish the book had been longer. I felt like I knew the characters and I wanted to know more. The authors were very respectful to the victim's family and I appreciated how the difficult subject was handled. I do however feel like there is a lot more to this story and I will be mining the internet for more information. Don't listen to this one around children; the details are lurid and not suitable for all ages.

True Crime Buffs Won't be Disappointed

Kat's confounding. Unsure where I fall in guilt/innocence question but authors fleshed out character well

Narrator cadence is off-putting

Narrator cadence and lack of inflection is so off-putting, I am unable to finish the book.

Sickest content.

This book is gratuitously sexual. It’s all disgusting uninteresting (except to perverts) and wildly unnecessary.
It’s aiming to be 50 shades for Crime readers. It’s childish and disgusting. Doesn’t interest me at all that they pretended to have multiple personalities in sex. It’s nonsense.