Forensic Entomology Enterprises
c/o M. Lee Goff, Ph.D.
45-187 Namoku St.
Kaneohe, HI 96744
21 Sept. 1998
Mr. Brent Davis
Second Judicial District of Arkansas
P.O. Box 491
Jonesboro, AR 72403
Dear Mr. Davis:
I have reviewed the materials you sent to me regarding the Affidavit of Dr. Neal H. Haskell relating to the petition for a new trial by Defendant Echols. In your letter, you posed a number of questions and I will respond to each here:
1. With respect to the question of Dr. Haskell's qualifications as a "forensic scientist" to comment on correlation between lividity, blanching and time of death, I do not believe he is qualified to offer an opinion as to time of death based on this phenomenon. In his affidavit, Dr. Haskell has cited references to the phenomenon and implied an opinion while not actually stating an opinion. As he does state, a forensic pathologist would be the appropriate individual for comment, not a forensic entomologist. By training, Dr. Haskell is a forensic entomologist.
2. With respect to possible injuries caused by fish or aquatic anthropods such as crayfish, I question that these could be determined from examination of photographs alone and without specific knowledge of the antropod and fish populations for the particular site. I do not find any suggestion that these data were available for this case. Even if these data were available, I doubt these would be of use in providing an estimate of the postmortem interval or the period of immersion in water. The second part of your question again goes to Dr. Haskell providing an opinion outside of his area of expertise, entomology. Unless he can demonstrate that he has conducted studies specifically designed to investigate these types of injuries or significant practical experience, I believe he is providing an opinion outside of his area of expertise.
3. The forensic entomologist determines the minimum postmortem interval or period of time since death by analyzing the species and developmental states of the insects present on a decomposing body. In many instances, this period will accont for the entire postmortem interval but this may not always be the case. There are factors which may delay access of insects to the body for oviposition or larviposition. These factors can include, but are not limited to, periods of darkness, temperatures below the threshold for adult fly activity, submersion of the body, wrapping of the body and burial.
The key point here is that the period determined is the minimum period.
3a. & b. In determining the minimum period of time through analyses of fly larva or maggot development, it is essential that the maggots be correctly identified to the species level. Differnt species have different patterns of reproduction and different rates of development. For example, flies in the family Calliphoridae typically lay eggs, while those in the family Sarcophagidae deposit first instar or first stage larvae directly onto the body. Recovery of first instar larvae of species of Calliphoridae indicates that a period of time required for hatching of the egg into the first instar larva has passed. By contrast, a first instar larva of a Sarcophagidae species may have been deposited on the body immediately prior to collection or observation. In this case, there were observations of maggots but no mention of eggs. Photographs you submitted show the bodies lying exposed on the bank of the ditch following removal from the water. During the period of time the bodies were exposed prior to transport to the funeral home, it is possible for Sarcophagidae species to have deposited the maggots in the natural body openings of the head, as noted by the Coroner in the Supplemental Reports. In the photographs submitted (#007156; 007168; 007174; 007176; 007177; 007236; 007303) there appeared to be blood present on the head. This would have been an attractant to flies for oviposition or larviposition once the bodies were removed from the water. As the maggots were not collected, no measurements made, or photographs taken specifically to demonstrate the maggots, no firm conclusions can be reached on this aspect, but there is a strong possiblity that the maggots were deposited following recovery of the bodies on 6 May 1993.
3c. The question of nocturnal oviposition or laying of eggs during periods of darkness is not completely resolved. While there is a general agreement among forensic entomologists that nocturnal oviposion is not the normal pattern, there has been some evidence of occasional nocturnal oviposition. In tempearate areas during periods of high temperatures, when a body or food source is placed in close proximity to resting adult female flies, egg laying does sometimes occur. Greenberg (1990, J. Med. Entomol. 27: 807-10) documented nocturnal oviposition by Calliphoridae species in Illinois. In tropical habitats, Calliphoridae may oviposit at night if the body is placed near their resting places (personal observations).
3d. If eggs or larvae were deposited in natural body openings prior to the body being submerged, there is the strong possibility that the eggs or maggots would have been washed off. In studies conducted here in Hawaii in intertidal areas and anchialine pools, permanent colonization of carcasses below the water line was prevented as the water washed off fly eggs and larvae (Davis & Goff, manuscript in preparation).
3e. Under these circumstances, the forensic pathologist would have been well advised to have preserved the maggots and consulted a forensic entomologist, simply to avoid later confusion of issues. As the evidence was not collected and preserved and there do not appear to be any photographic records available showing the maggots, involvement of a forensic entomologist by a defense counsel appears to have no real value to determining the postmortem interval. Typically, entomological evidence requires determination of the period of development of the maggots to estimate the minimum postmortem interval and is used after 24 hours of decomposition. In this case there is no basis for this activity. The total elapsed time between the last sighting of the victims and recovery of their bodies was 19.5 hours for Moore and they were pronounced dead and notes taken at a time approximately 22 hours after this last sighting. This time frame would have allowed for development of Calliphoridae from egg to first instar larvae or for first instar larvae to have been deposited by Sarcophagidae on the bodies while they lay on the bank following removal from the drainage ditch. One point which would tend to favor the latter scenario is that maggots were not noted in the area of the groin of Christopher Beyers but were seen in his eyes and nose. In invasion of a corpse by flies, the favored areas are the natural body openings associated with the head, followed by the genitals and anus. Wounds which occur before death (antemortem) or at the time of death (perimortem) while the heart is still beating are very attractive to flies due to the amount of blood present. Wounds produced after death (postmortem) when the heart is no longer pumping blood are not as attractive. In this case, it appears from the photogrtaphs that some blood was associated with the heads of the victims, but, from the photographs provided, I could not detect any blood associated with other parts of the bodies. This blood, although probably diluted, would have been attractive to adult flies once the bodies were removed from the water. The adults would then have first exploited the natural body openings of the head for depositing eggs or larvae. It should be noted that, the head would also have been closer to the edge of the plastic covering the body than the wounds associated with the groin, thus making the head more accessible to the files.
3f. The invasion of living tissues by fly larvae is termed myiasis. This condition does occur, but, given the cirumstances of this case, I would not anticipate this as an explanation of the presence of maggots on the bodies of the victims. Again, without specimens to examine to make species identifications, it is impossible to offer a definitive opinion but I believe this scenario is unlikely.
3g. The question of mosquito bites is interesting. I base my comments on my work (10+ years) with mosquitos as vectors of avian malaria here in Hawaii and personal experience with mosquitoes in California. Any bites inflicted on the victims by mosquitoes would have had to occur prior to their deaths. Adult female mosquitoes are obligate blood-feeding ectoparasites. They require blood from a living host and will not feed on a dead host. Male mosquitoes are nectar-feeders and can not take a blood meal. The tissue reaction to the mosquito bite varies in severity among individuals and is not an immediate reaction. A period of time is required for the inflammatory reaction to develop at the site of the bite. If the individual was killed prior to the reaction developing, there would be no area of inflammation visible. The bites of mosquitoes are relatively small puncture wounds and, lacking visible inflamation, these would not be readily apparent on a dead body. I have attempted to locate bites on bodies of dead birds, where the approximate site was known, with very limited success. A pathologist should be consulted with respect to the duration of inflammatory reaction following death. I do not feel that Dr. Haskell's conclusions that "they were not nude nor murdered in that brushy, wooded swamp like area" is supported by the lack of apparent mosquito bites.
My overall impression of the circumstancs of this case, based on the materials you have provided to me, is that a forensic entomologist would have been able to contribute little if anything to the resolution of the question of the postmortem interval for the victims or any other apsects of the case. Evidence was not collected and preserved which could be analyzed by the entomologist. The photographs I have examined do not provide any details which can be analyzed by an entomolgist. Speculations regarding potential significance of mosquito bites are not supported by the evidence presented. While there was an awareness of the significance of entomological evidence within the forensic pathology community in 1993, collections were not made and analysis, therefore, is not possible. Given the lack of entomological evidence, I do not feel the defense counsel would reasonably be expected to contact a forensic entomologist in the defense effort.
I hope this will be of use to you in your investigation. I am enclosing a copy of my current curriculum vitae for your information. Should additional information or clarification be needed, please feel free to contact me. As I mentioned earlier, I will be in Spain and Italy during the period 25 Oct. through 17 Nov. 1998, presenting workshops.
M. Lee Goff
Professor of Entomology
Diplomate and Chair of Executive Board,
American Board of Forensic Entomology