Jen J. Danna; Toronto, ON
Canadian forensic crime fiction author.

June 5, 2013

November 26, 2013

May 2014

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Word Count: Abbott and Lowell #5

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Human Remains in a Fire Scene

When human remains are found in a fire scene, the most important question is if the victim died of natural causes before the fire, was killed prior to the fire, or died as a result of the fire. Depending on the extent of damage to the body’s soft tissues, a coroner or medical examiner may be able to advise investigators. In some cases, a forensic anthropologist will need to be called in as a consultant.

When considering how to handle burned remains, the Crow-Glassman Scale (CGS) is a standardized sliding scale to describe the extent of burn injury:

  • CGS-1: a typical smoke inhalation death, including some burning and blistering of the skin. Visual identification is possible.
  • CGS-2: significant charring to the body, potentially including loss of the small bones of the hands and feet. Identification can be made by dental records and antemortem features of the deceased.
  • CGS-3: increased destruction of the body, although the skull is still intact. Visual identification is impossible at this stage and even large bones of the body may be disarticulated (larger arm or leg bones). Possible identification by dental records and/or DNA. A forensic anthropologist may be required to determine age, race and gender based on the skeleton.
  • CGS-4: total fragmentation of the skull and additional disarticulation of arm and leg bones from the body. A forensic anthropologist is required for any possible identification.
  • CGS-5: completely cremated remains. There is no remaining soft tissue and any remaining skeletal components are fragmentary. Identification based on the remains themselves is highly problematic.

In A FLAME IN THE WIND OF DEATH, it is the discovery of a CGS-3 body that requires the expertise of Boston University’s Dr. Matt Lowell. When Matt finds out that Trooper Leigh Abbott is not on the case, he balks until she is assigned and the team is brought together once again.

If a body falls into the first two CGS categories, a medical examiner should be able to determine based on soft tissue if the victim was alive at the time of the fire:

  1. If the victim was alive and breathing during the fire, he or she would inhale carbon monoxide produced as a by-product of the fire. Carbon monoxide binds to the hemoglobin in the blood producing the stable complex carboxyhemoglobin, displacing oxygen and leading to chemical suffocation because of insufficient oxygen delivery to the tissues of the body. Carboyxhemoglobin can be measured in blood; any level above 50% is considered lethal, although death has been shown to occur anywhere in the range of 20 – 80%, depending on the age and health of the victim.
  2. If the victim was alive and breathing in hot gases from the fire, the soft tissues in the throat will show a) soot deposits, and b) evidence of searing from the hot combustion gases. Soot can also be inhaled to such an extent as to cause mechanical suffocation.

If the victim does not show signs of fire-related death, then it falls to the medical examiner or a forensic anthropologist, depending on the extent of the burn injuries, to determine probable cause of death. In CGS-1 and most CGS-2 cases, a regular autopsy will suffice. But CGS-3 and CGS-4 cases require the knowledge and skills of a forensic anthropologist.

One of the biggest difficulties in determining cause of death in burned bodies is the fact that bones fracture in the intense heat of a fire. So differentiating perimortem (at the time of death) vs. post-mortem (after death) injuries is crucial. In the following lab scene from A FLAME IN THE WIND OF DEATH, Matt explains the difference to Leigh:

“First, you need to understand the difference between fractures in wet and dry bone so you can tell perimortem fractures from postmortem fractures. I know you’re familiar with kerf marks and how a solid object passing through bone leaves an imprint behind. In the same way, heat-induced fractures leave their own microscopic and macroscopic signatures. Using these signatures, we can reconstruct both what happened and the order in which the injuries occurred. The challenge in this case is the conformational changes that occur in bone exposed to extreme heat—it changes shape so you can’t simply fit the pieces back together cleanly. But the crucial point is that once there is an existing first fracture in a bone, a second break can’t cross it. That’s how you can map the order of injury.”

“Handy,” Leigh said. “But can you tell if a break was there before the fire?”

“Yes. Heat fractures are only formed under specific circumstances—the bone dehydrates causing it to warp and shrink. When that stress becomes excessive, it results in an abrupt break similar to a sharp force trauma fracture.”

“Doesn’t that cause problems, then? How can you tell between fire damage and sharp force trauma?”

“It’s a challenge,” Matt agreed. “But wet bone behaves differently. First, heat-induced fractures only happen in dry bone—bone that’s charred black or calcined. Normal bone doesn’t fracture from heat stress because the moisture content gives it too much resilience.”

Leigh swiveled to stare at the bones on the gurney. “So if there’s a fracture in uncharred bone, it happened before the fire.”


It is this analysis, confirmed by electron microscopy to corroborate fracture speed that helps the team determine the method of the victim’s death.

We hope you’ve all enjoyed this series of posts on fire investigations. It’s a fascinating subject and it certainly added an extra level of complexity to the case for our team!

A reminder to our readers that A FLAME IN THE WIND OF DEATH releases April 18th and be available shortly thereafter. This is the third installment in the Abbott and Lowell Forensic Mysteries, following DEAD, WITHOUT A STONE TO TELL IT, and the e-novella, NO ONE SEES ME ‘TIL I FALL.


Photo credit: p.Gordon


Challenges of Evidence Collection After A Fire

After a fire, a criminal investigation is officially launched if arson is suspected or when suspicious human remains are found. The biggest challenge in such an investigation is the scene itself, and the fact that much of the evidence is likely destroyed. But, sometimes surprisingly, robust evidence can still be recovered.

  • Fingerprints: Fingerprints are an organic slurry of amino acids and fats mixed with inorganic compounds. As with most organic compounds, they are at high risk of damage or destruction from both radiant and direct heat, water from hoses, and the soot and ash accompanying the smoke plume and the actual fire. Patent impressions (prints visible to the naked eye, often a transfer from a substance like ink or blood) can sometimes survive, even when the surface on which they are found is scorched or charred but still intact. In fact, some prints become even more ‘set’ with the fire’s heat. Modern detection methods—like chemical developers and lasers—are so superior to previous forensic tools that they can expose even heat-denatured prints. In some cases, the heat will bake the print, causing the oils in it to darken, turning it from a latent print (invisible to the naked eye without some form of detection method) to a patent print.
  • Tool impressions: Materials melt at different temperatures during a fire. So, while wood will ignite in the presence of flame at 350oC, aluminum won’t melt until 660oC, steel at 1430oC, and iron at 1535oC. Tool impressions made in higher melting temperature metals may very well survive the fire completely intact.
  • Fragment matches: In non-fire scenarios, the physical matching of fragments—rope, tape, fabric, concrete or glass—can connect a killer to his victim, or can assist in establishing a sequence of events. Even fire-damaged materials, if the edges are not badly disintegrated, can assist with this aspect of the investigation. Most glass in a fire is shattered by force or thermal shock, but as long as the majority of the fragments can be recovered, reconstruction of the original structure and matching of adjacent fragments can still be achieved.
  • Trace Evidence: This type of evidence, depending on the type, is the most frequently lost as a result of fire. Nevertheless much trace evidence can still exist, based on protected areas on a body or in the scene. Fiber, hair, paint samples, and soil can all be recovered from fire scenes, given the right circumstances.
  • Blood/DNA: Unless the body is nearly or completely charred to ash, the opportunity exists to extract blood from one of the cardiac chambers as they are well protected by the torso during the fire. An alternative strategy is to harvest tissue from deep within the quadriceps muscle of the thigh for DNA extraction. In A FLAME IN THE WIND OF DEATH, Massachusetts Medical Examiner Dr. Edward Rowe suggests both of these methods while the team is trying to identify burned remains. 

Next week, we’ll look more deeply into the damage fire does to the human body. When a victim is found in a fire, how can investigators identify the remains and determine the cause of death? We’ll be back next week with more…

A reminder to our readers that A FLAME IN THE WIND OF DEATH releases April 18th and be available shortly thereafter. This is the third installment in the Abbott and Lowell Forensic Mysteries, following DEAD, WITHOUT A STONE TO TELL IT, and the e-novella, NO ONE SEES ME ‘TIL I FALL.


Photo credit: Public Domain Photos


Forensics 101: Fire Investigation

Last week we talked about some of the basics of what is involved in fire investigation and who takes part. This week we want to look more closely into what is involved in a fire investigation.

Before even setting foot inside the cooled and potentially stabilized building, a thorough investigation takes place outside the structure, taking into account an arsonist’s possible entry and exit routes, existing sightlines for any potential witnesses, and evidence external to the scene (sometimes this is the only intact evidence that escaped the fire). After entering the scene, the fire investigator is focused on two primary issues—the fire's point of origin and its cause.

To determine the point of origin, the investigator essentially needs to create a virtual reconstruction of the site as it existed before the fire based on burn and fire protection patterns. This requires analysis of the fuel involved in the fire, ventilation, the direction of spread, fire duration, and the materials involved. After reconstructing the flow and outward spread of the fire, the investigator can then follow it backwards to where it started.

What knowledge and tools must a fire investigator have at his disposal to reconstruct the devastation of a fire scene? In A FLAME IN THE WIND OF DEATH, Trooper Bree Gilson of the Massachusetts Fire Marshal’s Office uses a combination of all these strategies to determine the point of origin:

  • Fire dynamics: Fire investigators must be intimately aware of the driving factors in any fire—heat transfer and the buoyancy of hot combustion gases. If those gases reach a temperature of more than 500oC, they become visible as a fire plume. The larger the fire, the taller the fire plume and the more hot gases and particulate matter rise above it in the smoke plume.
  • Heat transfer patterns: How materials are affected by fire varies with the characteristics of that material—its melting temperature and thickness (thin materials transfer heat more rapidly than thick materials). Direct exposure to flame will also affect a material faster than radiant heat. Since the most severe thermal damage and the associated highest temperatures often indicate the point of origin, heat patterns on walls and ceilings will often reveal the location of the initial fire.
  • Soot layering: Soot—composed of carbon particles produced by the incomplete combustion of organic material—is a by-product of fire. These particles are contained in the hot gases and smoke that rise above the fire plume, spreading outward along the ceiling. When those hot gases encounter colder surfaces of the structure that are not yet involved in the fire, the soot particles condense in a layer on that surface. Therefore, if a part of the structure that was fully involved in the fire also shows evidence of soot, then that area of the fire started after the initial blaze.
  • Knowledge of materials: The behaviour of materials in a fire, i.e. the temperature at which thermal damage will affect that material, is crucial in fire investigation. For instance, copper will melt in an 1100oC fire, but steel and iron will not. Glass will melt at 760oC, but if heated to lower temperatures and then rapidly cooled by water spray, a web of microfractures called ‘crazing’ forms within the structure of the glass. Study of the materials in a fire will indicate where the fire started (heavier thermal damage will be located nearest to the seat of the fire), and also provide the direction of travel.


  • Interviews with firefighters: Structure conditions can change rapidly while crews extinguish the fire. Often windows are purposely broken by firefighters to ventilate the fire, so post-fire structure condition does not necessarily indicate the initial state of the structure. Interviews with firefighters will indicate conditions at the time of their arrival, as well as throughout the operation. Smoke and ventilation conditions—if doors were left open or if windows were open or broken at the time of arrival—can indicate the direction of travel of the fire prior to the fire fighters’ arrival.
  • Full photographic documentation: Once the scene is released and outside individuals are allowed access, the scene can no longer be considered as untainted evidence. Photographs of the state of the scene prior to release are crucial for later reference and courtroom testimony. Also, since burned structures may be unstable as water-logged walls fall or hot spots rekindle, prompt photos are crucial to document the scene as soon as possible after the fire. Since roofs often collapse during a fire, crucial evidence may be obscured by debris landing inside the structure. Sequential photos must be taken as layers of the scene are removed, revealing additional evidence.
  • K-9 investigators: Many fire departments are assisted by K-9 team members who are trained to isolate and locate the smell of chemical accelerants, helping to determine both the point of origin and the cause of the fire.


In cases where a K-9 has not identified an accelerant, the cause of the fire must be determined after the point of origin is located. In some cases, a fuel or heat source may be self-evident by the presence of a heated appliance such as a stove or iron. Some fires clearly lead back to wall sockets, extension cords, or small electrical devices that have failed or been misused. If an accelerant is suspected, samples can be taken from the point of origin for chemical testing.

Next week, we’re going to look at criminal fire investigations and the challenges of collecting evidence when your scene has been destroyed.

A reminder to our readers that A FLAME IN THE WIND OF DEATH will release April 18th and be available shortly thereafter. This is the third installment in the Abbott and Lowell Forensic Mysteries, following DEAD, WITHOUT A STONE TO TELL IT, and the e-novella, NO ONE SEES ME ‘TIL I FALL.




Photo credit: State Farm and DaveBleasdale


Fire Scene Reconstruction and Investigation

The third installment in the Abbott and Lowell Forensic Mysteries—A FLAME IN THE WIND OF DEATH—releases next month. As part of that event, we want to spend the next few weeks talking about some of the science that went into the book—both fire investigation and murder investigation following a fire.

During a fire, the first concern is to rescue any people or pets who might be in danger, followed by protection of that structure and adjacent structures. But once the fire is out and has cooled, the primary concern shifts to determining the cause of the blaze.

Depending on the jurisdiction, this investigation may be carried out by a fire marshall with arrest powers, or local police forces may be called in to assist. In Massachusetts, the location of the Abbott and Lowell Forensic Mysteries, the state Fire Marshal doesn’t actually investigate; instead, Massachusetts State Police troopers with full investigative powers are assigned to the Fire Investigation Unit. In A FLAME IN THE WIND OF DEATH, we introduce a new character to the Abbott and Lowell Forensic Mysteries—Trooper Brianna ‘Bree’ Gilson from the Massachusetts State Fire Marshal’s Office. A former Salem fire fighter, Bree has crossed over to the police side of fire investigation, training to become a state trooper with the intent of joining the Fire Marshal’s Office. Because of her past experiences as a fire fighter, Bree proves to be a significant asset to Matt, Leigh, and the team in solving two fire-related deaths.

If any victims are found during the course of the investigation, the site is immediately considered a crime scene until investigators can determine the victim’s cause of death. In Massachusetts—with the exceptions of Boston, Springfield and Worcester which all have their own local homicide departments—officers from the Massachusetts State Police Detective Units are called in investigate all fire deaths.

The main difference between homicide and fire reconstructions is the destruction of the scene during a fire, compounded by the action of the fire fighters. Not only have multiple people stormed through the detective’s homicide scene, but items have been displaced by water (200 psi water streams pack a significant punch), melted by heat, and possibily exposed to weathering by elements such as ice and snow after the destruction of the surrounding building. It’s often a signficant challenge for both the homicide investigators and the fire marshal to determine what happened on site before the fire took hold.

Leaving aside potential deaths, what are the questions and challenges faced by the fire marshal? There are several main questions that must be answered in any fire investigation:

  1. What is the point of origin of the fire?
  2. What was the cause of the fire?
  3. Was the fire accidental or intentional?
  4. What accelerants might have contributed to the fire and its subsequent growth?
  5. Who or what was responsible for the fire?
  6. Were any crimes commited concurrent to the fire i.e. breaking and entering, burglary, or murder?

If arson is suspected, three things must be proved:

  1. Physical destruction is a result of the fire.
  2. The fire was started deliberately.
  3. There was specific intent to start the fire—murder, monetary gain etc.

In the case of an associated death, several additional questions must be answered:

  1. What caused the death?
  2. What links the two occurences?

A death associated with a fire is not necessarily homicide; perhaps someone had a heart attack while cooking dinner and a subsequent stove fire burned down the house. But the possibility that a fire might have been set to destroy evidence and mask the identity of a victim must always be considered.

Next week, we’ll delve more deeply into fire investigation and explain how investigators determine the point of origin and how the fire started.

A reminder to our readers that A FLAME IN THE WIND OF DEATH will release April 18th and be available shortly thereafter. This is the third installment in the Abbott and Lowell Forensic Mysteries, following DEAD, WITHOUT A STONE TO TELL IT, and the e-novella, NO ONE SEES ME ‘TIL I FALL.

If you want a chance to read our newest release weeks before it's available in stores, this is one of your last chances to win a free, signed ARC. Enter to win 1 of 3 copies in the Goodreads giveaway here!


Big Publishing News for Abbott and Lowell Forensic Mysteries!

Ann and I are thrilled to have not one, but two publishing deals to announce today!

First of all, the paperback rights for DEAD, WITHOUT A STONE TO TELL IT have been contracted by Harlequin Worldwide Mysteries. We’re thrilled that our debut novel will now be available in three formats—hardcover, ebook, and paperback—for accessible reading no matter what your preference. Recent discussions with Harlequin indicate a moved-up release date of December 2014 to the very early part of 2015. More on that when we know more.

But our really big news is that the fourth installment in the Abbott and Lowell Forensic Mysteries, TWO PARTS BLOODY MURDER, has been accepted for publication by Five Star Publishing, which has released all the full length novels in our series to date. Described by our editor as our best book so far, we love this book for its blend of mystery and history.


Publishers Marketplace recently published the two official announcements. Big thanks to agent extraordinaire Nicole Resciniti of the Seymour Agency for all her work on these deals:

March 3, 2014 - DEAD WITHOUT A STONE TO TELL IT by Jen Danna and Ann Vanderlaan 
Fiction: Mystery/Crime
Jen Danna with Ann Vanderlaan's DEAD WITHOUT A STONE TO TELL IT, when a single human bone is found on a lonely stretch of coastline, a determined homicide detective and a reluctant scientist risk their lives when they join forces to bring a serial killer to justice, to Laura Barth at HQN Worldwide Mystery, in a nice deal, for publication in Fall 2015, by Nicole Resciniti at The Seymour Agency (NA).

March 13, 2014 - TWO PARTS BLOODY MURDER by Jen Danna and Ann Vanderlaan
Fiction: Mystery/Crime
Jen Danna with Ann Vanderlaan's TWO PARTS BLOODY MURDER, the fourth book in the Abbott and Lowell Forensic Mysteries, where a body discovered in a long-forgotten speakeasy proves to be ground zero for a cascade of murders through the decades, to Deni Dietz at Five Star, in a nice deal, for publication in Spring 2015, by Nicole Resciniti at The Seymour Agency (NA).


TWO PARTS BLOODY MURDER will be released either in March or April of 2015, so we’re pleased that this will keep the release of each installment in the series to less than a year apart. We can only write so fast because I still work full time in the research lab, but keeping the series rolling with regular release dates is very important to us.

So… what’s coming up next for Matt, Leigh and their team?


Prohibition was a time of clandestine excess—short skirts, drinking, dancing . . . and death. But a murder committed so many years ago still has the power to reverberate decades later with deadly consequences.

It’s a double surprise for Trooper Leigh Abbott as she investigates a cold case and discovers two murder victims in a historic nineteenth-century building. Together with forensic anthropologist Matt Lowell and medical examiner Dr. Edward Rowe, she uncovers the secrets of a long-forgotten, Prohibition-era speakeasy in the same building. But when the two victims are discovered to be relatives—their deaths separated by over eighty years—the case deepens, and suddenly the speakeasy is revealed as ground zero for a cascade of crimes through the decades. When a murder committed nearly forty years ago comes under fresh scrutiny, the team realizes that an innocent man was wrongly imprisoned and the real murderer is still at large. Now they must solve three murders spanning over eighty years if they hope to set a wronged man free.

A reminder to our readers that A FLAME IN THE WIND OF DEATH will release April 18th and be available shortly thereafter. This is the third installment in the Abbott and Lowell Forensic Mysteries, following DEAD, WITHOUT A STONE TO TELL IT, and the e-novella, NO ONE SEES ME ‘TIL I FALL. To mark this event, next week we’re going to start a series of posts on fire investigation and forensics. Please join us for this fascinating topic.