August 1, 2018 Vol. 1, No. 2

Sifting the Ashes

The Importance of Ventilation

Underwriters Laboratories Fire Safety Research Institute (FSRI) is conducting a series of full-scale burn tests at their facility in Northbrook, IL. These tests are funded by the US Department of Justice and are intended to help firefighters extinguish fires more safely, and to help fire investigators to better understand the effects of ventilation.

I was honored to be invited to serve on the Technical Panel of Fire Forensics, which provides outside guidance for this set of much-needed experiments.

The final report has yet to be presented, but there is a seven-minute YouTube video showings on the work that has been done.

The two graphs on the next page show the interdependence of temperature and oxygen concentration, and are reproduced from the Third Edition of Scientific Protocols for Fire Investigation, currently in press.

Figure 3.13 (b) Graphs showing the relationship of temperature to oxygen concentration in a test fire. Flashover occurred at just over 200 seconds. The oxygen concentration dropped at the same time, and the temperature dropped precipitously as well. (Courtesy of Underwriters Laboratories, with permission)

Case Study of the Month

This month's case study provides details of a fatal fire caused by a candle that resulted in false charges of arson and homicide. It is a story of incredible incompetence as well as a story of a man of integrity standing up to the powers that be, a stand that cost him his livelihood, but at least he didn’t have to sell his soul.

State of Georgia v. Linda and Scott Dahlman

Frances Dahlman suffered a severe stroke that left her paralyzed on the right side. She had initially been placed into a nursing home, but her son, Scott, and his wife, Valerie, were not pleased with the quality of care that Frances was being provided, so they had their basement refinished and built a mother-in-law suite for her. Additionally, they hired a nurse to stay with Frances for 12 hours a day and took care of her themselves for the balance of the time. Frances was in hospice care because in addition to her stroke she had a heart condition as well, and was not expected to live more than a few months. She had a standing “Do Not Resuscitate” order and her doctor had advised that her medications (she took both blood pressure and anti-seizure medicines) were optional. The stroke left her vulnerable to violent seizures, which caused her to flail her left arm.

There was a large supply of morphine sulfate in the house (a bottle was found on the table next to Frances’s chair), so if Valerie or Scott had decided that it was time to end Frances’s life, they could have done so easily, and there would have been no questions about the cause of death. In fact, there would have been no autopsy.

On the morning of August 31, 2008 at 5:27 AM, there was a fire on and immediately next to Frances’s chair, and she was badly burned. She was transported to Grady Hospital in Atlanta where she died of her injuries a few hours later.

Valerie Dahlman reported discovering her mother-in-law on fire, and used a garden hose to extinguish her. But when the fire investigators first arrived at the scene, some of them were suspicious. Frances had a “Perfect Chair,” which was electrically powered to allow her to change position. The chair, immediately after the fire is, shown in Figure 9.7 (a). The Peachtree City Fire Marshal took the chair into custody, and the police sent other evidence to the Georgia Bureau of Investigation (GBI) Division of Forensic Services (DOFS).

Examination of the chair by an electrical engineer retained by the City Fire Marshal revealed that there was burning on one of the 110 V cables in the chair, but this burning was almost certainly a result of exposure to an advancing fire. Because there was a death involved, on September 8, a Deputy State Fire Marshal was called in. The Fire Marshal inspected the chair and photos of the scene, but apparently not all of them.

The State Fire Marshal prepared his first undated report, which was just over a page long. It is unknown when he decided that this fire was incendiary, but the medical examiner’s autopsy report, dated April 7, 2009, (more than seven months after the fire) stated, “A thorough investigation failed to reveal the source of the fire thus the manner of death is undetermined.” [1]

Using negative corpus methodology, this Fire Marshal concluded,

The area of origin of the fire was determined to be within the area of the side of the chair and the blanket on the floor. Obvious sources of ignition in the area of origin were investigated. All accidental causes were eliminated as the possible cause of the fire. (Emphasis added.)

Upon completion of examining all the photographs and evidence available of the fire scene and examination of the chair it is my opinion the chair Ms. Francis Dahlman was sitting in at the time of the fire was intentionally set on fire with criminal intent. [2]

On November 30, 2009, some 15 months after the fire, Valerie was arrested, and ordered held without bond. On December 16, Scott was arrested as well. Despite the fact that he had offered to turn himself in, the police insisted on coming to his home and arresting him in front of his children.

Figure 9.7 (a) Photo of the electrically operated “Perfect Chair” taken at 5:58 AM, before the smoke had completely cleared. Note that the hospital table had been pushed aside by first responders.

The Dahlmans had recognized early on that they were the targets of a criminal investigation and retained highly respected defense attorneys Ed Garland and Richard Grossman. The author was retained by Mr. Grossman on September 12, 2008, and made a trip to Atlanta to examine the chair on September 17, and concluded that the chair could not be blamed for the fire. After the arrests, I visited the Georgia State Crime Laboratory on March 10, 2010 where the evidence other than the chair had been taken. Among the items of evidence was a candle on a saucer that had been burning on a hospital table immediately to Frances’s left. The fire pattern on the almost entirely burned candle and saucer suggested that perhaps an item of bed clothing such as a sheet or blanket had been inadvertently placed on the saucer and caught fire. The crime laboratory had identified fibers embedded in the candle wax, but concluded that these fibers did not match the blanket that was

Figure 9.7 (b) Photo of the candle and other items on the hospital table, taken at 6:19 AM. The objects clearly are arranged differently than they are in the next photo.

submitted. The candle was clearly visible in fire scene photos as shown in Figure 9.7 (b)

Throughout the pendency of these murder charges, I was curious as to why I had not seen a report from the Peachtree City Fire Marshal. He was one of the first people on the scene and had collected evidence and videotaped the scene. Unfortunately, his communication with the deputy State Fire Marshal was less than ideal, possibly because of a difference of opinion as to the fire cause. It was more than a year after the fire that the State Fire Marshal learned about the existence of the candle, an “obvious source of ignition in the area of origin.”

In a preliminary proceeding, the judge was dismayed by the bare-bones quality of the state fire marshal’s initial report and requested another one. In the second report, which revealed his thought processes more extensively, he wrote about the candle, (note: grammatical errors are in the original)

There is no way to determine or confirm when the melting and blackened residue occurred because subsequent interview with the caretaker stated that she, Ms. Dahlman’s son and daughter-in-law would light a candle and leave it on the table to sooth Ms. Francis Dahlman. I did have the opportunity to examine the candle and saucer itself because they were taken as evidence. Closer examination of the blackened residue appeared to possibly be soot that would have landed on the saucer as the result of unburned by products of the chair floating down and landing on the saucer. …

Through deductive reasoning I was able to eliminate the candle as being the ignition source of the fire. First observation was the lotion bottle exhibited fire damage to the paper attached to the bottle on one side of the bottle. However, the fire damage of the paper on the lotion bottle was on the opposite side away from the area of origin and the area of radiant heat and fire that would have been caused by the fire. I also observed the candle exhibited melting out of the far side of the candle which again was further away from the fire. In conclusion the fire damage exhibited to the lotion bottle and candle is not indicative of the damage you would see if they had been close to the side of the electric chair. Therefore it was my determination through deductive reasoning that the candle was eliminated, was not close to the chair, and was not the ignition factor of the electric chair burning. …

There was no fire damage found anywhere on the hospital table not even any soot, which would have been indicative of the table being next to the chair at the time of the fire. Therefore, it is my determination the table and the items on the table can be removed from the equation thus if the table was not close enough to the chair to sustain fire damage or receive any soot accumulation the candle can be eliminated as the ignition factor of the fire. …

As to the theory and elimination of another possible accidental cause which has been mention by the caretakers that Ms. Dahlman would with her mental status and condition have seizures and spells of wildly swinging her arms around and possibly threw the blanket over onto the candle which was actually located behind her chair. It is common sense this would not have been possible without knocking or dragging items off of the hospital table. …

Upon completion of examining all the photographs and evidence available of the fire scene and examination of the chair and with the information received and the on-scene investigation completed, it is my opinion the cause of this fire is intentional and incendiary in nature. [3]

Figure 9.7 (c) Photo of a reconstruction of the origin area, taken at 7:22 AM. The location and orientation of the objects on the table is unsupported by smoke patterns or any other evidence.

Let us now consider the Fire Marshal’s “deductive reasoning.” First, he did not say when he examined the candle and saucer, or if he had actually seen them or just photographs. He stated that the soot on the saucer had landed there by “floating down.” If that were the case, there should have been evenly distributed soot elsewhere, and there should have been a protected area under the saucer. No such evidence existed. So the smoke particles selectively landed on the saucer? Next, the observations about the items on the table were misplaced. The photo, Figure 9.7 (c) from which these “observations” were made was a reconstruction. The City Fire Marshal had requested the reconstruction from the first responders, but there is no way to tell how accurate their reconstruction was. They were focused on the patient, not the artifacts around her. The image of the reconstruction was made at 7:22 AM on the day of the fire. Figure 9.7 (a) was shot at 5:58, while there was still smoke in the room, and Figure 9.7 (b) was shot at 6:19 AM. These photos were taken by Cpl. Hyatt of the Peachtree City Police Department between 5:57 and 6:25 AM. On a second set of images including the reconstruction, there is another photo showing the chair prior to the reconstruction, taken at 7:13 AM. Even someone with minimal computer skills should be able to look at metadata to determine the provenance of an image. Due to the lack of smoke deposits on the table, there is no way to discern the location, much less the orientation of the objects in the photo. The Fire Marshal thus relied on demonstrably unreliable “data” to “eliminate” the candle as the ignition source. Not explained in the second report is how the fire on the chair could damage the “paper” (actually plastic) on the opposite side of the lotion bottle. Violating the laws of physics was no problem for this individual, because, despite being an IAAI-CFI, he did not understand the laws of physics.

When the City Fire Marshal was finally compelled to render an opinion, he stated that the cause of the fire was “undetermined.” He knew about the candle, but because the state fire marshal, the police and the prosecutor told him they had “something,” he refrained from making a determination. After the arrests in December 2009, he had told the ADA that he did not believe this was an arson case. Further, the videotape he had made was made available to the State Fire Marshal and it showed a burned white sheet that had not been collected as evidence. The sheet, which may have been the source of the fibers that the GBI Laboratory found in the candle wax, certainly should have been tested for wax. The failure to collect the sheet was blamed for the case not being prosecuted.

The district attorney stated:

The white sheet was not photographed, seized, entered on any chain of custody, secured or properly maintained by the Peachtree City Fire Marshal and was thus not considered by the State Fire Marshal in his fire scene analysis. The white sheet is not now available. The state believes the above, when considered with other evidence available to the state at this time will create a reasonable doubt as to the guilt of the accused and that while there was probable cause for the arrest, there is insufficient evidence to prove guilt beyond a reasonable doubt. [4]

The white sheet was certainly photographed in the video. The fire patterns did not show when it was ignited, but it could have been the first fuel ignited. There was, however, already plenty of reasonable doubt in this case. The DA dismissed the case because he was going to lose, with or without the loss of the white sheet.

Because he would not go along with the incendiary determination made by the State Fire Marshal, the City Fire Marshal was demoted and eventually left the fire service. To this day, John Dailey stands as an example of someone who would not sacrifice his integrity, even at the cost of his livelihood.

The State Fire Marshal, on seeing the videotape still insisted that the fire was incendiary, apparently because once he has made an incendiary determination, even with compelling new evidence, there is never any going back. The State Fire Marshal’s office stated “ … our opinion does not change that this fire was intentionally set,” and “Hopefully, the DA will revisit this case.” [5]

9.7.1 Error analysis

The city Fire Marshal surely should have photographed and retained the white sheet, and poor communication resulted in the State Fire Marshal not learning about the candle for over a year and the white sheet until almost two years after the fire. The State Fire Marshal, however, should have inquired about the evidence that was collected before he arrived on the scene. He also should have reviewed the first responder’s photographs. Instead he relied on a reconstruction that could not be verified. There is no excuse for overlooking either the first photographs or the critical evidence that was in the possession of the Georgia Bureau of Investigation. He relied on negative corpus methodology to decide that the fire was incendiary. That Fire Marshal then decided to discard that data that was inconsistent with his determination, coming up with a physically impossible explanation for the smoke deposits on the saucer.

9.7.2 Significance

This case caused quite a stir in the local fire investigation community and resulted in a Fire Marshal losing his job for the supposed reason that evidence had been lost but for the real reason that he would not go along with the prosecution. John Dailey set an example for people who are asked to do something that they know is wrong. Scott and Valerie Dahlman have resumed their lives after the trauma of losing Scott’s mother and the even worse trauma of being accused of a horrific crime. This is one case where the background information should have persuaded even the most suspicious investigators that arson homicide was not a reasonable hypothesis. Under what circumstances would a couple having the means and opportunity to kill someone quietly and painlessly decide instead to burn the victim alive? The State Fire Marshal has retired.


[1] Eisenstadt, J., (2009) Autopsy Report, GBI DOFS, dated April 4, 2009.

[2] Gourley B., (2009) Georgia Insurance and Safety Fire Commissioners Office State Fire Marshals - Arson Unit, undated first report on the Dahlman fire.

[3] Gourley B., (2010) Georgia Insurance and Safety Fire Commissioners Office State Fire Marshals - Arson Unit, Supplemental report on the Dahlman fire, prepared on or before March 8, 2010.

[4] Sellers, W., (2010) State of Georgia v. Scott David Dahlman and Valerie Lynn Dahlman, Case No. 2009R-0533, Nolle Prosequi dated May 10, 2010.

[5] Garner, M., (2010) “Investigative error causes murder case against couple to be dropped,” Atlanta Journal and Constitution, May 16, 2010.

A closer view of the candle and saucer. The highly localized smoke deposits were erroneously characterized as “blackened residue [that] appeared to possibly be soot that would have landed on the saucer as the result of unburned by products of the chair floating down and landing on the saucer.”

Deep Thoughts About Forensic Science

A website review by John J. Lentini, CFI, D-ABC

In April 2018, the Seton Hall Law Review published a symposium celebrating the career of Dr. Michael Risinger, one of the leaders of the movement to improve forensic science, and a dear friend. This symposium consists of papers written by ten legal scholars with expertise in the forensic sciences. Two of the papers reference fire investigation and some even mention my work over the last 25 years.

U C Irvine Criminology Professor Simon Cole’s paper “Who Will Regulate American Forensic Science?” discusses the response of the forensic science community to the 2009 National Academy of Sciences report “Strengthening Forensic Sciences in the United States: a Path Forward,” particularly the Organization of Scientific Area Committees (OSAC) hosted by the National Institute of Standards and Technology (NIST). Dr. Cole is critical of the response because it does not, in his opinion, contain sufficient numbers of non-practitioners in the standards development organizations.

As a practitioner who has tried to invite new stakeholders to the standards development table, I can only say to Dr. Cole that it is very difficult to persuade judges and lawyers to sit in a room with scientists and wordsmith standards documents. It is hard enough for the people who know what they are doing. Nonetheless, Cole’s call for a “scientific culture” in forensic science is worth heeding. He closes by asking “Has NIST’s OSAC assembled just the right mix of scientific firepower, practitioner buy-in, consumer pressure, government power, cultural change and persuasive force to be the entity that finally reforms forensic science? We cannot yet know, but the task is daunting.”

Professor Cole’s paper may be found at this link:

A second paper that also addresses fire investigation directly has the daunting title of “Toward a Sociology of Forensic Knowledge: A (Supplementary) Response to Cole.” This paper is written by Prof. David S Caudill of Villanova University School of Law, and takes a different approach to forensic science. Caudill argues that forensic science should be set up like medicine, where some of the scientists do the heavy research lifting, but don’t see patients, and others treat patients, but don’t conduct research. He refers to the researchers as “contributory experts.” The other kind of experts are what he calls “interactional experts.” These experts can immerse themselves in the science, but will not necessarily contribute to the development of the science. They have the technical skills, however, to run the tests and report the results that the judicial system needs. Caudill compares the medical model to the relationship between fire protection engineering (where the research happens) and fire investigation (where the investigating happens) to illustrate his point, and quotes an article that I wrote for Criminal Justice in 2012 where I stated,

“Certainly it is possible for individuals with no chemistry or physics beyond high school to apply themselves and learn the basic science and keep up with developments in the field.”

Caudill concludes by stating, “The notion that a realistic goal may be to encourage forensic cultures in synch with science, rather than full-blown scientific cultures finds support in the effort to identify reliable experts irrespective of their level of formal education.”

As an undergraduate, the most valuable advice I received came from my organic chemistry professor who said, “Think about what you're doing!” Those who want to think about what they’re doing in forensic science in general or fire investigation in particular would be well served by taking the time the articles in this excellent symposium.

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