Madison Knight and a police car silhouette with light flashing. Stiles Police Detective badge with yellow tape - POLICE PROCEDURALS RESPECTED BY LAW ENFORCEMENT.TM
Madison Knight and a police car silhouette with light flashing. Stiles Police Detective badge with yellow tape - POLICE PROCEDURALS RESPECTED BY LAW ENFORCEMENT.TM

In the Line of Duty (Detective Madison Knight Series)

In the Line of Duty by Carolyn Arnold badge with morning band covering the middle of the badge resting on a rippled US flag.

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In the Line of Duty by Carolyn Arnold badge with morning band covering the middle of the badge resting on a rippled US flag.

Listen to a sample of In the Line of Duty narrated by Hayley Palmaer.

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Her fellow officer has made the ultimate sacrifice, and Detective Madison Knight may have to lay it all on the line to bring his killer to justice. But with leads pointing in several directions, she has to narrow them down—and quickly—if she’s going to solve the case before anyone else gets hurt, including herself.

$5.99 USD e-book

5-Stars-for-Books-Small Rating 4.9 stars*

Author: Carolyn Arnold
Series: Detective Madison Knight Series, Book 7
Genres: Hard-Boiled, Mystery, Detective, Police Procedural
Publisher: Hibbert & Stiles Publishing Inc.
Year: 2016
Length: 295 pages

Audiobook: 978-1-988064-28-4 – Narrator: Hayley Palmaer
Print ISBNs: (4 x 7) 978-1-988353-24-1, (6 x 9) 978-1-988353-25-8

Book Overview for In the Line of Duty

He devoted his life to seeking justice. But would she get any for him?

It was an ordinary day for police officer Barry Weir. It was the end of shift, he was tired, and he just wanted to get home to his wife and kids. But someone had other plans for him, shooting him down and forcing him to make the ultimate sacrifice.

When news of Weir’s murder reaches the department, it leaves Detective Madison Knight and every cop in the Stiles PD itching for revenge. It cuts Madison’s boyfriend, colleague, and Weir’s childhood friend, Troy Matthews, deepest of all, driving him away from everyone he loves just when they need one another the most.

With evidence pointing to a gang-related drive-by, Madison and her team investigate the town’s seedy underbelly in search of justice for their fallen brother. But the deeper they dig, the more convoluted the case becomes. Now they need to figure out if this was a random shooting as part of a gang initiation, a straight-up hate crime, or a targeted kill. But with members of the Stiles PD under attack, they have to do it fast…before more officers pay with their lives.

Testimonials & Reviews for In the Line of Duty

“A simply riveting read from cover to cover, In the Line of Duty clearly reveals author Carolyn Arnold to be a master of the genre with an exceptional flair for creating truly memorable characters and a roller-coaster ride of a plot with all manner of twists and turns… Very highly recommended.”
–Midwest Book Review

“Fans of crime fiction will be moved and enthralled by In the Line of Duty, as much an action-packed mystery as it is a heartfelt tribute to police who give up their lives to protect others.”
–Publishers Weekly

“This story is especially viable in this time period with the unrest we’ve seen on nightly news reports. The author does an impressive job with police procedures while keeping the emotions real and heart-wrenching for these characters… A very well-written book!”
–Jacquie Biggar, USA Today Bestselling Author

“Carolyn Arnold’s love for law enforcement and providing an accurate depiction of their job is clearly evident in her writing. She is eager to have police procedures spot on, both in tactics and investigations. It’s this enthusiasm paired with her knack for storytelling and her realistic portrayal of police work that makes her an author that mystery readers would enjoy reading, including those with a law enforcement background.

“You experience the emotions, distractions, frustrations, and successes of the characters in every chapter of In the Line of Duty.  I found her heartfelt details to be spot on with a line-of-duty death. Being able to put such a tragic situation into words, is difficult in itself, but she does it with compassion, knowledge, and respect for those in uniform who know what it is like to lose a brother or sister in blue.”
Carl J. Harper, Training Officer, ERT (SWAT), Lower Merion Township, Pennsylvania

“This story was gut wrenching with the emotions of the police officers when an officer goes down. Madison vows to catch the shooter but the leads are all over the place. Madison and Troy’s relationship suffers as he shuts her out as the officer shot was his best childhood friend.  The author did a wonderful job with the characters and their reactions and the bread crumb clues leave you entertained while not letting you know who did it. This is one book you won’t know who did it until the END!”
–Paula Harp, Harps Romance Book Review

“This is a sobering and intriguing look at an investigation that is all too pertinent to officers who risk their lives every day… an up-close and authentic-feeling look at the process of dealing with the fatality of a fellow officer and the impact that reverberates through the entire team. The exhaustion and negative emotions that must be dealt with are vividly portrayed, as is the painstaking effort that goes into an investigation. At times it seemed that events were proceeding very ponderously but ultimately the exciting climax provided both revelations and a satisfying conclusion. I think this story will be appreciated by those who would like an in-depth look at the workings of a police force as well as those who enjoy an urban mystery.”
–The Reading Addict

“The book can be read standalone if you haven’t read the others in the series.  The author has done her research on how police departments run… All of the characters are well written.  If you enjoy law enforcement books, you will appreciate this novel.”
–Felita Daniels, Lilac Reviews

“WOW. That was my first thought upon finishing this story. This was a superbly done mystery/police procedural that managed to perfectly blend action with suspense and “dead end” leads. The author also managed to tread that careful line between accurately portraying grief and loss (especially due to a line of duty death), while managing NOT to make the story depressing.

“I enjoyed these characters, the drama and tension that they brought to the story, while maintaining the camaraderie of people who work closely together each day. I also enjoyed the way the author was able to bring to life the steps and stages of an active investigation. This story was not one of those “cut and dry” stories where the culprits are easy to figure out. In fact – this one kept me guessing right up until the very end! I was also more than surprised at how the end of this story played out.

“Even though this is billed as “Madison Knight #7”, please do NOT let that discourage you from reading! I have not read any prior novels in this series, and I had no trouble at all following along. It would seem that the only thing this story has in common with the other ones is the cast of main characters.

“Overall, I would definitely recommend this novel to anyone who enjoys a well-written police procedural that is full of surprises! This might have been the first story in this series (and by this author) that I have read, but it will certainly NOT be the last!”
–Krystal, Red Wine and Books

“I’m picky when it comes to police procedurals. While I love watching them, they don’t always come across well in book form for me. Either they’re lacking in character development, or the twists aren’t very twisty, or the plot drags at some point, etc. So I was a bit wary about trying In the Line of Duty. Would it work for me? Would it really live up to the claim “Police Procedurals Respected by Law Enforcement?” I’m happy to say that it did.

“I don’t want to reveal too much, but suffice to say, I enjoyed this book. The characters were nuanced and real. I could feel the grief Madison and her fellow officers were suffering due to the death of one of their own. And I could feel the urgency that they put into finding out answers. The plot twists kept coming, with red herrings and surprises keeping me (and the cops) guessing throughout the book…I greatly enjoyed reading In the Line of Duty and since this is book 7 in the series (but it still works as a standalone), I would love to read the others in order to learn more about Madison and her crew.”
–Emily, Sharing Links and Wisdom

“Each of the Madison Knight books work well as stand-alone novels. And, like its predecessors, In the Line of Duty lays out the cold, hard realization of life on the blue line. And, unfortunately echoes an all-too-real event in today’s world … the death of a fellow officer… I thoroughly enjoyed the character development of the heroine as she works her way through a failed relationship. It brought a new depth to the book. Author Carolyn Arnold does a wonderful job portraying what it’s like to be out there in the real world as a police officer on a day-to-day basis. Her facts are accurate and the book is well written. For fans of police procedurals, this book certainly delivers.”
–Nancy Fraser, Notes from a Romantic’s Heart

In The Line of Duty by Carolyn Arnold is the 7th book of her Madison Knight series.  One thing you can be certain when reading this series; Carolyn Arnold will give us an intense exciting murder mystery, as well as provide us with accurate details pertaining to police procedurals.   When it comes to police investigations & procedurals no one does it better than Arnold.  Madison Knight is a tough detective, who will let nothing stand in her way to find the guilty.

“A policemen is murdered in what is suspected to be a gang killing, and the entire Stiles PD are working together to find the murderers.  There were a number of twists that continued to change the game, as to who was truly behind the killing; with some surprises all the way through.

In the Line of Duty was also a complete turnaround for Madison; something I have been asking for quite some time.   Madison has finally found love in her boyfriend Troy, who is the leader of the Swat team.  Her friend Cynthia has also stepped up to be a good friend, not to mention a great medical examiner.  The Stiles PD Sergeant has finally opened his eyes as to the value of Madison as a top notch detective.  Things changed in this book that I absolutely loved, and Madison finally has a team surrounding her, and the respect she so deserves.   Thank you, Carolyn.

“Rather than give spoilers, In the Line of Duty was a great story, with lots of action, precise investigations, many suspects, and a team atmosphere to solve the crime.   I loved seeing Madison falling in love with Troy, and finding time to care about and enjoy her friends.  I enjoyed this story so much; I could not put the book down; especially with new developments changing constantly.  This story was very exciting and well written.  If you enjoy mysteries, murder cops, police procedurals and a tough as nails cop, then you need to be reading this series.”
–Barb Liebman, The Reading Café

“Police officers are taking a lot of heat now a days–yes there are bad cops–but many more of them are good and really do want to help and protect the general public. Personally I have a grudge against the Meter Maids–but that is a story for another day! Even when it is one of their own that has been shot down they attempt to keep a cool head–but they will track whoever did it down and as quickly as possible as this novel portrays.

“When Police Officer Barry Weir is shot down while pumping gas-he leaves behind a wife and children–and shocked and very angry coworkers. They vowed to get the person(s) who did it–and none more then Detective Madison Knight and her boyfriend Troy Mathews who is part of the SWAT team. Barry Weir and Tony were childhood friends. Tony withdraws from everything in his profound grief and concentrates only on finding out who did this.

“It appeared to be a random drive through killing by one of the local gangs possibly—-but was it? The twists and turns will have your head spinning. When the entire truth is found out–you will find yourself gasping and possibly like me shaking your head.”
–Michele Bodenheimer, Miki’s Hope

“A beautiful, well-written, emotional book. I loved the mystery and the suspense. Just enough suspense and mystery to keep me loving and reading.

“This is the seventh book in the series and it’s my first book that I read. I didn’t get lost when I read it. I understood what was going on. Enjoyed the plot, characters. A very [well] written story for sure. We all need to thank our police for doing their jobs [and for putting] their lives on the line every day.”
–Stacey Schneller, Books, Dreams, Life

“Although In The Line Of Duty is the seventh Detective Madison Knight novel in the series, it is the first I have read and I was glad not to have any problems with missing information spoiling the storyline. The murdered police officer narrative is entirely self-contained and cracks along at a thrillingly fast pace – so fast that at times I found myself muttering the ‘more haste, less speed’ maxim at certain characters! Our lead, Madison, is particularly headstrong and gung-ho and, while this makes for exciting fiction, I wondered how well her attitude would be tolerated in a real police station. An obligatory burgeoning romance side-story between Madison and SWAT team leader Troy adds additional heartbreak to an already emotional theme.

“I liked that Arnold doesn’t milk the emotional aspect too much. As a reader I could feel the grief of her characters and their strong sense of loss, but this was never made mawkish or excessively sentimental. I was swept up in the solving of the crime and there is a nicely tangled web of suspects and motives to unravel. Thinking back in order to write this review, there are a couple of moments that jarred and the forensic work does all seem to be completed at superhuman speed, but overall I think this is a great escapist read if readers just go with the flow and don’t question everything too deeply! I would happily read other instalments in this series.”
–Stephanie Jane, Literary Flits

“An intense, action-filled police procedural, In the Line of Duty by Carolyn Arnold, is filled with colorful characters, good dialogue, a solid mystery and plenty of emotional angst.  While this is the seventh book in the Madison Knight series, this is a book which can be read on its own. If you like reading solid mysteries, a strong female protagonist, and police procedurals with plenty of action, this is a book and series you will definitely want to check out.

“Ms. Arnold does a great job introducing her main character, Madison Knight, right from the start. A single, female detective, Madison is a hard working detective, who is giving romance, with a fellow cop, a second chance. I easily connected with Madison right from the start; she’s had to work hard to prove herself in a job still mainly occupied by men and has also had to deal with family, which is less than thrilled about her dangerous profession. A fact which becomes the focus of this installment as Madison, and her fellow cops, are forced to deal with the murder of one of their own. As Madison begins the investigation she’s upset at the loss of a fellow officer, thankful that her boyfriend Troy, the leader of the S.W.A.T. team wasn’t a victim, and filled with anger that someone would shoot a cop in the line of duty.

“The secondary characters are well developed and while most of them are recurring characters, Ms. Arnold does a good job introducing them, and their role in Madison’s life, so that new readers don’t get lost. I especially liked getting to know Troy better, and watching Madison’s natural skills as a leader take charge. The mystery is well developed and at the start there are plenty of suspects and possible motives. As Madison and the rest of the squad continue to investigate the shooting, it becomes clear that gangs are involved and that the police have a target painted on their backs.

“The story’s pace is fairly rapid and Ms. Arnold’s voice as an author is strong and very easy to follow. There are several twists and turns, some that made me wonder if Madison and her team were looking at the right suspects, which kept me glued to the pages of the story. There is plenty of action and a lot of emotional angst as the officers go about the investigation while dealing with grief and the emotional fallout that this type of situation brings about. It’s hard to convince your family that others need you “to protect and serve” while someone is shooting your fellow cops and your family wonders if you will make it back home alive.

“Will Madison discover who killed her fellow officer and why? Will her romance with Troy, a fellow cop, survive the investigation? You’ll have to read In the Line of Duty to find out. I really enjoyed it and look forward to reading the next installment in this thrilling series.”
–Maria Durst , Queen of All She Reads

“Anyone who loves police procedures will love this book. It takes you in a step by step sequence to show you how the police operate and how they conduct investigations. And in this book, the investigation is dear to the hearts of the entire police force as they hunt for a cop killer.

“The plot of the story is complex with many layers which makes the investigation even more complicated. It’s headed by Madison Knight and Troy Matthews who previously entered into a relationship that is complicated by past hurts and disappointments. Their fears are exacerbated by the loss of one of their own, and whether they’ll survive as a couple is in some question.

“The book is suspenseful as the investigation moves to its conclusion, and you find yourself hoping for a satisfactory ending. It’s a good read that I enjoyed. 5 stars.”
–Elaine Cantrell, Hope. Dreams. Life… Love

“This book was such a good book. I started it Thursday night, and finished it Friday evening. It was fantastic!… This book absolutely kept me guessing until the killer was revealed. I felt that the story was very well written. The twists and turns will leave your head spinning, in a good way. I had my guesses throughout the book who could have done such a hateful crime, and I was wrong every time. I’ll be honest, and say that when the book was almost over and they were going through the funeral for a cop, I teared up.

“Prior to reading this book, I had no ideas that it was a part of a series. I don’t think I would have ever guessed it was a part of a series, because I felt like the author clued us in on everything we needed to know, and didn’t leave anything out.”
–Jessica Cali, Cali Book Reviews

“This was my first read of Carolyn Arnolds and I enjoyed it so much. As a massive fan of Blue Bloods and Chicago P.D., I figured this would be a great read! And I was right!!

“I loved Detective Madison Knight’s character, she was totally badass and goes in guns blazing! There is so much packed into this read with chasing leads that ended up getting us nowhere and I found myself getting just as frustrated as the characters. Just when I though YES they got him, something else was thrown into the works and it was back to square one all over again and the drawing board.

“I’ll tell you one thing though this book definitely kept me on my toes, it wasn’t boring at all. Packed full of action and suspense you will get into this just as much as Carolyn Arnolds characters and that just goes to show what an amazing writer she is. The drama and tension will keep you turning the pages until the very end. It is an emotional read at times as they each deal with the loss of their “Fallen Brother”, but it’s especially hard for Madison as the officer shot was her partner, Troy’s, childhood best friend. Madison and Troy’s relationship takes its toll as he pushes her away and that leads Madison to do everything and anything to catch the killer, so they better watch out……

“I would definitely recommend reading this book even though it says book #7 that is OK as this was my first read in the series and the author makes it really easy to follow.”
–Dawn Walsh, Irish Daisy Loves Romance

“I am a huge fan of suspense and mystery novels. In the Line of Duty is a great story that had me on the edge of my seat… this story was filled with emotions and it is very well written. This story had me wondering what came next in some parts and had me crying in others. Carolyn Arnold did a great job with the plot and the characters!

“This is the seventh book in this series, however it is the first I have read. I liked that I never felt lost or not sure of what was going on. So this is definitely a great stand alone read. Even though I don’t have to, I will be reading the other six books though because I really liked this one.”
–Silvie Armas, My Silly Little Gang

“When Detective Madison Knight received the call that a fellow officer was shot, she had no idea just how much it would impact her emotionally. As Madison works feverishly following leads and suspects, she has to keep her emotions in check personally, as well as emotionally… This was a fast paced story, with a roller coaster of emotions.”
–Julie Baswell, I Create Purty Things

“A hard hitting, emotional novel which covers the true meaning of comradeship and team spirit. The loss of a close colleague stirs the full range of emotions from anger to sorrow.  It also tears the relationship within the investigation squad to pieces.

“The excellent descriptive writing brings the characters to life and the most impressive part of it is the human element that is portrayed and will touch the heartstrings of the reader.  The investigation route takes us on a roller coaster of ride through a page turning twister of a thriller.  You get a real feeling of what it is like to work and live in a close community like the police force, where everyone knows each other’s families and the tragedy runs deep.

“A riveting read and if you like a thriller you need to read this book.”
–Beck Valley Books

In the Line of Duty is the seventh book in the Detective Madison Knight series. Having never read the previous books in the series, I was a bit worried that I would not be able to follow the story. However, my worries were unnecessary. This book can be read as a stand-alone.

“This story is a demonstration of what the persons who swore to protect and serve face on a daily basis.  It also demonstrates the trauma and turmoil they face when one of theirs is taken down by ruthless criminals. This was a story of real human emotions that hit too close to home.

What stood out most to me in this story is the manner in which grief can either bring people together or pull them apart. In this instance, I saw officers who could barely tolerate each other, working together to achieve a common goal. Also, I saw the toll it took on Madison’s relationship with her significant other.

“The characters were interesting, but the one that stood out for me was Madison. She was a kickass detective who was fearless, strong-willed and tenacious. She followed all possible leads as she was committed to solving this case. She confronted everything head on. I loved how the author portrayed both her personal and professional life. It shows her struggling to gain approval from her mom who does not approve of her career choice. This showed that there is a sensitive side to her kickass detective who was fearless, strong-willed and tenacious. She followed all possible leads as she was committed to solving this case. She confronted everything head on. I loved how the author portrayed both her personal and professional life. It shows her struggling to gain approval from her mom who does not approve of her career choice. This showed that there is a sensitive side to her.

“The story was gripping. I could not wait to find out who was responsible for the killing and what was the motive. There were so many possible suspects. Just when I thought I had it figured out another suspect was thrown into the mix.  When all was revealed I was in utter shock as I never saw it coming.

“I am impressed with her writing style and how she portrays her characters. It is evident that she had done her due diligence before putting pen to paper. Her attention to detail was on point and the way she described each scene made me feel as if I was actually there.

“This is a must read for fans of police procedurals.”
–Nadene, Totally Addicted to Reading

“A gripping story with a few twists and turns along the way… Arnold creates characters with depth. Written in a way that keeps you engaged and wanting to know what happens next, the author creates cohesive dialogue that is enjoyable to read.

“You could feel the tension leap from the page and that made the read so much more intriguing. Even though this is the seventh book in the Madison Knight series, this is my first Carolyn Arnold book. That being said, it will not be my last.”
–Sherry, Recommended Romance

“I absolutely loved this book. I have not read any other books in the series, but I will certainly make an effort to seek them out now! I could see it being a movie. I even have an idea of who could play some of the characters, but I will keep that to myself for now. I thought it was great that the author makes such an effort to do her research on police procedures. I also love that I was kept guessing as to who might have done it, and I was surprised when the full story was laid out. Definitely not who I was expecting!… Carolyn Arnold is now on my list of authors to read more work from. And Madison is a great character that I will be following from now on!”
–Hilary Mahoney, Elusive Red Tiger

“Carolyn Arnold has created an undeniably, great read that you won’t put down…. The time and effort put into learning “behind the scenes” police operations is a big plus for creating an accurate story-line that will resonate with readers who have a sense of respect for police officers. From page one, I fancied myself as a detective to become ‘involved’ in the story. By the end of the book, I am about 95% positive that I would have been fired for my lack of discovery. The twists and suspense had my head spinning and just when I thought I had it all figured out, the finale made me exhale with a resounding, “Whoa!

“Madison’s character is extremely well-written and realistic. She encompasses what all women should strive to become — an independent thinker, strong-willed, dedicated, hardworking and yet, still holds onto a tiny piece of hope in the dream of acceptance from her mother.

“Don’t miss out on the chance to grab this book! You’ll immediately find yourself immersed!”
–Lynchberg Mama

“I loved it! It was a wonderfully twisted mystery that led the detectives (and me) on a wild goose chase.”
–Leila, Leels Loves Books 

“A gripping, suspenseful story, and highly recommended to anyone who enjoys a good mystery read.”
–Majanka, I Heart Reading

Author Readings

*Rating based on

Other Books in the Detective Madison Knight Series

Ties that Bind by Carolyn Arnold jogger’s feet on asphalt surface with police tape over it faded over an image of a check pattern tie

Ties That Bind

Justified by Carolyn Arnold blood spattered money on a green background


Sacrifice by Carolyn Arnold winter scene, water and snow with necklace and pendent engraved with CC on a blue gray background


Found Innocent by Carolyn Arnold image of a man's boot on a shovel being pushed into the ground on a orange background

Found Innocent

Just Cause by Carolyn Arnold woman holding a pistol pointed at you and a police car silhouette with flashing lights on a midnight blue background

Just Cause

Deadly Impulse by Carolyn Arnold Stripper over an image of a dark alley with a dumpster on a dark teal background

Deadly Impulse

Power Struggle by Carolyn Arnold, a man and woman in a standoff on a city street at night.

Power Struggle

Life Sentence by Carolyn Arnold good looking couple in front of a mansion with flames coming up from the bottom on a forest green background

Life Sentence

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