Sifting the Ashes

April 1, 2019, Vol. 2, No. 4

Accreditation is on the Horizon

The quality assurance paradigm in forensic science (which includes fire investigation) is defined by the forensic science quality triangle, shown in Figure 1.

Fire investigators have long had the benefit of two legs of the quality triangle, certification and standardization. Certification has been available from the International Association of Arson Investigators (IAAI) since the mid 1980s and The National Association of Fire Investigators (NAFI) since the early 1990s. Investigators are currently held to a standard for certification, National Fire Protection Association (NFPA) 1033, Standard For Professional Qualifications For Fire Investigator.

Standard methodology can be found in NFPA 921, Guide for Fire and Explosion Investigations, which has been available since 1992. The third leg of the triangle, accreditation has, until recently, been the weak link in fire investigation quality assurance. That is about to change.

Figure 1. The Quality Triangle in Forensic Science.

(Proficiency testing is beyond the scope of the current discussion)

To my knowledge, there are only three fire investigation organizations currently accredited, and until accreditation becomes more commonplace, it will not be considered meaningful whether a fire investigation unit is accredited or not. The accreditation provided comes from the American Association for Laboratory Accreditation, known as A2LA. This organization has so far accredited the Forensic Investigations Group of Covington, LA (, Iris Investigations of Englewood CO (, and the Abu Dhabi Police Forensic Evidence Department in the United Arab Emirates.

These fire investigation units are accredited in accordance with the recognized international standard ISO/IEC 17020:2012 Conformity Assessment-Requirements for the Operation of Various Types of Bodies Performing Inspection. These organizations also meet the requirements of A2LA R318-Specific Requirements: Forensic Examination Accreditation Program-Inspection.

ISO/IEC 17020 is a very general document, and in order to achieve accreditation, the organizations were required to essentially write their own standards in the form of a quality assurance manual.

Recognizing this deficiency in the availability of standards, the Organization of Scientific Area Committees (OSAC) Subcommittee on Fire and Explosion Investigations proposed to the NFPA that they develop a standard for the operation of fire investigation units. At its December 2018 meeting, the standards counsel of NFPA voted to approve the proposed scope of the technical committee on fire investigation units as follows copy from the NFPA website.

The Council voted to approve the proposed scope of the Technical Committee on Fire Investigation Units as follows:  

APPROVED SCOPE:  This Committee shall have primary responsibility for standards relating to the development and composition of Fire Investigation Units (FIU). This committee does not have responsibility for the development of standards relating to fire investigation techniques, methodologies, or fire investigator professional qualifications.

The Council voted to approve the roster of the Technical Committee for Fire Investigation Units.  The Council also voted to approve interest classification clarifications for the Technical Committee on Fire Investigation Units with an editorial correction to Consumer additional clarification as follows: 

Additional Clarification: Any entity engaged in the practice of reviewing FIUs against the standard (both public and private). 

There already exists a very general NFPA standard, 1730, Standard on Organization and Deployment of Fire Prevention Inspection and Code Enforcement, Plan Review, Investigation, and Public Education Operations but the guidance on the operation of an FIU is minimal.

The OSAC subcommittee prepared a rough draft of a new standard for fire investigation units, which it then passed on to NFPA, which can use it as a basis for the new NFPA standard if it so chooses.

One thing the new standard will not do is require that fire investigation units become accredited, but the standard will provide a basis to support accreditation, just as NFPA 1033 provides a basis to support certification.

The most difficult part of becoming accredited is writing the quality assurance (QA) manual that describes how the unit operates. An accrediting body then audits the unit to make sure that they say what they do in the QA manual and that they do what they say. In order to facilitate the writing of a QA manual, the OSAC Subcommittee has begun drafting a QA manual for a generic fire investigation unit, which can then be adapted by each unit. This generic QA manual should be available from OSAC by the end of the summer.

Although the scope of the new NFPA Technical Committee on Fire Investigation Units specifically excludes writing qualifications criteria, there is nevertheless some overlap between accreditation and certification.

Under “Resources,” ISO/IEC 17020: 2102 has requirements for personnel as follows:

6.1 Personnel

6.1.1 The inspection body shall define and document the competence requirements for all personnel involved in inspection activities, including requirements for education, training, technical knowledge, skills and experience.

NOTE The competence requirements can be part of the job description or other documentation mentioned in 5.2.7. (5.2.7 reads, “The inspection body shall have a job description or other documentation for each position category within its organization involved in inspection activities.”)

6.1.2 The inspection body shall employ, or have contracts with, a sufficient number of persons with the required competencies, including, where needed, the ability to make professional judgments, to perform the type, range and volume of its inspection activities.

6.1.3 The personnel responsible for inspection shall have appropriate qualifications, training, experience and a satisfactory knowledge of the requirements of the inspections to be carried out.

The Texas Commission on Fire Protection (TCFP) has produced a rigorous 128-page Certification Curriculum Manual for Fire Investigators that meets the above ISO requirements. The TX CFP curriculum is directly tied to NFPA 1033 and NFPA 921. Investigators would be well advised to visit the site and read this manual, because this is what is going to be expected of us in the future.


Case Study of the Month

Alabama v. Kum Sun Tucker

This month’s case study involves a fire where investigators may have read too much into the timing of the fire, though it certainly was suspicious. The fire occurred in the summer of 2012, but the case was not resolved for more than four years.

Ms. Tucker was a 59-year-old Korean woman who operated a beauty supply store shown in Figure 1, located in a strip mall in Mobile, AL. She had a very poor grasp of English and mostly communicated through family members.

Figure 1. Front of the Beauty Supply store.

Business had not been going well lately, and Ms. Tucker was nine months behind on her rent, totaling $16,000. The landlord had offered her a remedy to catch up, but she had not signed the revised lease. Further, she had allowed her liability and property insurance, required by the lease, to expire.

The timing of the fire, however, was the most suspicious element. The fire happened at 3:15 AM on a Saturday morning, and video on a nearby business captured Ms. Tucker's van leaving the business only 10 minutes prior. She was headed to a flea market in Montgomery, where she sold handmade silk flowers. Although the time of the fire seemed strange, Ms. Tucker was known to drive up to Montgomery in the early morning hours of every Saturday.

The investigator from the city identified the origin as being at a doorway between the retail area and the storage area at the back of the store. A sample of carpet collected from this area tested positive for medium petroleum distillate (MPD). He originally labeled the fire as “undetermined with suspicious circumstances.”

After the insurance company’s origin and cause investigator reached a determination of undetermined but “foul play suspected,” he called in an electrical engineer who ruled out all electrical causes. Some 14 months after the fire, the original investigator, having failed in his multiple attempts to interview Ms. Tucker because of the unavailability of a Korean translator, decided that this was a case of arson. Ms. Tucker was arrested in December 2013 and an indictment followed in May 2014.

Ms. Tucker's family originally retained private counsel who did not see the necessity of hiring an expert. In November 2015, the original counsel withdrew from the defense and was replaced by an able attorney who recognized the necessity of having an expert to advise him in the defense of an arson case. Because the defendant was by now indigent, counsel requested and was granted funds for an expert. Consequently, I was retained in February 2016.

I reviewed the chemical analysis and found that both the public and private sector laboratories had correctly identified medium petroleum distillate, but the photographs of the scene, particularly photographs of the alleged origin area where there appeared to be containers of cleaning products, made me suspect that the MPD may have been “incidental.” These containers are shown in Figure 2. Further, the chemical analysis revealed the presence of limonene and iso-menthol. These fragrances strongly suggest that a cleaning product may have been the actual source for the MPD. The laboratory report, however, only stated, “Products in this range include, but are not limited to, mineral spirits, some paint thinners, some charcoal starters and some lamp oils.” This is a common, if somewhat misleading, practice among fire debris laboratories. Investigators should know that products not intended as fuels such as insecticides and cleaning agents can leave ignitable liquid residues (ILRs). For more information on incidental ILRs, please see “The Petroleum-laced background” at

Figure 2. Supplies at the base of the doorway identified as the area of origin.

In reviewing the fire pattern analysis, it became apparent to me that there might be some ambiguity as to the point of origin. Just to the right of the doorway that had been identified as the origin, there was a desk, and a hot plate on top of that desk had been examined and eliminated as a potential cause because the hotplate was not plugged in. What was not stated in the original report was that the hotplate sat on top of a microwave oven. This microwave was visible in the public sector photos, shown in Figure 3 but it had apparently been moved by the time the insurance company investigators came in. Figure 4 shows a wider view of the wall with the doorway, the microwave and the desk.

Figure 3. Hot plate sitting on top of the microwave. The hot plate was eliminated, but there is no indication that the microwave was ever examined by anyone.

Both the public and private sector investigators identified the origin on the basis of the lowest and deepest char, which as has been pointed out in previous newsletters is not always the best candidate for the origin. There did appear, in fact, to be another V-shaped pattern emanating from the desk, and a number of movement patterns around the desk brought me to the conclusion that the origin was not necessarily on the floor, but maybe was on the desk.

Figure 4. East wall of the storage room, showing proximity of the microwave to the alleged area of origin.

A fire advancing onto the desk from another location might be expected to leave a protection pattern behind the microwave, as shown in Figure 5. Instead, when the photographs taken by the insurance investigator were examined, the plywood wall behind the microwave was charred completely through, as shown in Figure 6. This strongly suggested that there may have been a malfunction in the microwave.

Unfortunately, the microwave was not available for inspection having not been collected as evidence during the original investigation or the subsequent investigation by the insurance carrier.

Defense counsel made a motion that the state produce the microwave for inspection, and because they were unable to do so, made a motion to dismiss based on spoliation of evidence. That motion was denied, but the prosecutor was made aware of witnesses in his case, and the court took under advisement an “adverse inference” charge to the jury based on the loss of the microwave. Such a charge allows but does not require a jury to infer that had the lost evidence been available, it would have been helpful to the defendant.

Figure 5. Shaded area shows where there should have been a protection pattern if the microwave were attacked by an advancing fire.

Meanwhile, Ms. Tucker suffered a stroke and was hospitalized for several weeks, further delaying any proceedings. While the court recognized the need for an interpreter, it was difficult to find one.

The evidence showed that the fire in the storage area had some of the indicia of flashover, but did not quite get there. There was an aluminum ladder, which had the top melted off, as shown in Figure 7. This requires hot gas layer temperatures in the range of 600° C, which is often identified as the beginning of flashover.

Figure 6. Close up view showing charred wood behind the microwave. The absence of a protection pattern and the depth of char make this a more likely origin than the doorway.

Figure 7. The hot gas layer melted off the top of the aluminum ladder at the right.

After several months of back-and-forth motions, because of her frail medical condition and her desire to be done with this ordeal, Ms. Tucker entered a plea known as a “best interest” plea of guilty but without an admission of guilt. She was not required to pay restitution, and was placed on “informal probation.” Defense counsel and I were prepared for a trial, and had a PowerPoint ready to show the jury, but the plea deal was just too good to pass up. That PowerPoint, as well as other source documents such as reports, motions and photographs may be viewed and downloaded at this link:

This case has several important lessons. The first is to consider alternatives to the “lowest and deepest char.” A fire originating on the desk would not be expected to move downward, but one spreading from the desk to the hollow core door a few feet to the left would be expected to cause drop-down and low burning in the doorway. The next lesson is to document and save evidence that has been considered and eliminated, or risk a claim of spoliation of evidence.

As the quality of some of these photographs demonstrate, it is always better to come back in the daytime when there is enough light to get good images.

Given the apparent strength of the case against his client, defense counsel thought that the retention of an expert to review the case may have been going through the motions of “due diligence.” The 10-minute time frame was pretty powerful evidence against the defendant, but there were problems with the State’s case. The location of the origin was certainly not optimal if Ms. Tucker had wanted to cause maximum damage, nor would she have closed the door between the retail area and the storage area. The lack of insurance on the considerable amount of merchandise in the store raises the issue of what her motive possibly could have been.

In most of the cases I am asked to review, there is sufficient evidence to support the original investigator’s hypotheses about origin and cause. I am often retained just to help counsel avoid claims of ineffective assistance. Sometimes, however, the review leads to a defense lawyer’s worst nightmare: a potentially innocent client.

A note about these case studies

These case studies are intended to raise awareness of issues that may come up in any fire investigation. The level of detail presented in this Newsletter is not nearly as deep as it would be if presented in a report or in testimony. I don’t want to lose the interest of people who just want a synopsis. For most of these studies, I have provided links to source documents and images for those who really want to get into the granular details. As always, I welcome any questions or comments that readers may have.

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