The Skull in Concrete: A Multidisciplinary Approach to Identification
Written by Kristen Hartnett-McCann & Ruth E. Kohlmeier   

IN AUGUST 2016, A BICYCLIST went to look for a place to relieve himself in the woods off of a highway in New York when he discovered a human skull partially embedded in concrete. He was intrigued by some antique glassware he saw on the ground and then noticed a concrete mound with what appeared to be a human skull inside. The bicyclist contacted the county law enforcement, who responded to the scene. At the scene, law enforcement confirmed a cement mound with an opening at the top, exposing a human skull partially embedded in cement and lying on its right side (see Figure 1). A cervical vertebra was located adjacent to the cement mound, and another cervical vertebra was resting on top of the skull. A search of the adjacent wooded area by law enforcement detected no additional bones or evidence. The concrete mound and associated bones were transported to the county medical examiner’s office where they were documented, photographed, and x-rayed. The medical examiner assigned to the case recognized a multidisciplinary analytical approach would be best, given the unusual circumstances. Thus, the medical examiner enlisted the expertise of a forensic anthropologist, forensic odontologist, forensic artist, trace evidence scientist, and a DNA specialist to maximize the information that could be gleaned from the remains and concrete.

 

Figure 1. Concrete mound with embedded human skull found near a highway in New York.

Forensic Anthropological Analysis

After the initial examination by the medical examiner, the forensic anthropologist carefully extracted the skull from the cement mound using a hammer and a flat-head screwdriver as a chisel. Small sections of the upper portion of the cement mound were chiseled away until the skull could be lifted out. The remains consisted of one nearly complete human skull (see Figure 2), the body and right greater horn of the hyoid, and three cervical vertebrae (C2, C3, and C4). The teeth were in good condition, and several restorations were observed. The remains were skeletonized, dry with no soft tissue, insects, or odor of decomposition, and exhibited brown staining as well as sun bleaching. A small amount of scalp hair was found with the cranium, also embedded in the concrete. Overall, the remains exhibited taphonomic changes consistent with internment in concrete (while still fleshed) for an extended period of time – at least two years but likely longer.

Figure 2. Anterior (A) and left lateral (B) views of the cranium present for analysis. The mandible is present but not shown here.

The forensic anthropologist had a difficult time estimating ancestry because the cranium exhibited features consistent with European (White), Asian, and Hispanic ancestries (Hefner, 2009; Rhine, 1990), but did not seem to fall clearly into one group. European (White) traits included receding zygomatic bones, projecting anterior nasal spine, and no alveolar prognathism. Asian traits included a moderately wide nasal aperture with a slightly guttered nasal sill and a round cranium (see Figure 2). Metric discriminant function analyses were also performed using Fordisc 3.1 (Jantz & Ousley, 2005). When tested against all males in Fordisc 3.1, this individual grouped with both Asian and European (White) individuals but was not very typical of either group.

Forensic stature was not estimated because the postcranial limb elements were absent. Sex was estimated using the morphological features of the cranium (see Figure 2.2): the supraorbital tori were large, the mastoid processes were large, the supraorbital margins were blunt and thick, the nuchal muscle attachments were large, and the mental eminence on the mandible was large and square (Bass, 2005; Buikstra & Ubelaker, 1994). In addition, a logistic regression discriminant analysis of the morphology of the skull yielded a determination of male (Walker, 2008), and a metric analysis of the cranium using Fordisc 3.1 (Jantz & Ousley, 2005) was also consistent with a male individual. The broad age interval was based on the cranial sutures (which appeared mostly open), and the presence of a fully erupted mandibular left third molar.

The forensic anthropologist observed both antemortem and perimortem trauma on the remains present for analysis (see Figure 3). Antemortem (healed) fractures were visible on the nasal bones. A combination of perimortem sharp and blunt force trauma was observed on the right parietal, temporal, and frontal bones (see Figure 3). The sharp force defect had a sharp superior margin as well as associated concentric, depressed, and radiating fractures. Hair was embedded in the large concentric and depressed fracture on the parietal bone. A fracture was also located on the right maxilla, medial to the zygomaticomaxillary suture.

Sharp force defects were observed on the squamous and basilar portions of the occipital bone, on the right mastoid process, and on the ascending ramus of the right side of the mandible. A portion of the occipital was missing, and concrete was present in the defects. These defects may be perimortem sharp force trauma to the back of the head but could also be associated with postmortem removal of the head at the neck. Furthermore, sharp force defects were noted on the superior and inferior aspects of the body, spinous process, and inferior articular processes of the fourth cervical vertebra. These defects are likely associated with the removal of the head through transection with a sharp instrument between C4 and C5.

Figure 3. Right lateral aspect of the cranium. A perimortem sharp force defect with associated radiating, concentric, and depressed fractures is present on the right parietal, temporal, and frontal bones. The concentric fractures are indicated by the large white arrows and the sharp margin of the defect is indicated by the smaller white arrows.

Identification

Unfortunately, a manual review of possible matching cases in NamUs was unsuccessful; no antemortem dental radiographs or records matched the postmortem radiographs of the unknown decedent. Hair was attached to the skull and the cement where the skull had been partially embedded. Hair samples were submitted to the Trace Evidence division of the County Crime Laboratory. Microscopic examination of a representative sample revealed light brown, brown, and dark brown human head hair fragments exhibiting European (White) racial characteristics. The hair fragments were unsuitable for microscopic comparison and nuclear DNA analysis but appeared suitable for mitochondrial DNA analysis. A portion of the mandible and one tooth were submitted to the Forensic Biology division of the County Crime Laboratory for nuclear DNA analysis. DNA from the tooth was extracted using the EZ1 DNA Investigator Kit. Quantitation of the DNA extracts was performed using the Quantifiler Duo Kit. The polymerase chain reaction amplification of short tandem repeats was performed using the Identifiler Plus PCR Amplification Kit, and the amplified DNA was analyzed with capillary electrophoresis. The bone sample was extracted and quantitated but no further analysis was conducted on this sample because positive results were already obtained from the tooth. The DNA profile from the tooth was entered into the local DNA database and submitted to the state and national DNA databases. There was a match between the tooth and another sample in the local CODIS database, which happened to be bone submitted from a 2009 case in the same county involving dismembered human remains discovered in a landfill. The 2009 case had been previously positively identified via DNA from a toothbrush of a 36-year-old male from Pakistan who had been missing since 2007.

The medical examiner reviewed the autopsy report, photographs, investigation notes, and anthropology report from the 2009 case, illustrating how clear and accurate documentation is important because it may be relevant to cases down the road. According to the 2009 documentation, the decomposing and dismembered remains were discovered in a New York landfill by sanitation workers. This particular landfill was very busy and received construction trash from multiple sites, including New York City. The remains included only the mid-cervical neck, torso, and portions of the upper and lower extremities. Clothing was present, and the remains were enclosed in black plastic bags with silver tape. The medical examiner described the remains as an adult European (White) male, based on the soft tissue still present. A forensic anthropologist determined the age was between 30 and 50 years based on the examination of the sternal rib ends, pubic symphyses, and 6th rib histology. Sharp and blunt-force trauma consistent with postmortem dismemberment was observed on two mid-cervical vertebrae, at the distal left humerus and olecranon process of the left ulna, distal right humerus, and midshaft of the right and left femora. The skeletal evidence indicated that the head, forearms, and lower limbs at mid-thigh were removed using a sharp implement, such as a knife or other beveled instrument, in a hacking or chopping motion. The dismemberment trauma observed on the vertebrae in the 2016 case was consistent with the dismemberment trauma described on the vertebrae of the 2009 case. The medical examiner ruled the cause of death in the 2009 case as “Homicidal Violence, Type Undetermined,” and the manner of death a “Homicide.” At the time, a segment of femur was submitted for DNA analysis. A local CODIS database (LDIS) search yielded a match between the mitochondrial DNA (mtDNA) sequences and nuclear DNA profiles generated from the femur of the 2009 unidentified male to that of a toothbrush used by a missing person. Coincidentally, the forensic photographer documenting the skull in 2016 vividly remembered the 2009 torso because he was interviewing for his position the very day it came in. In 2016, he still remembered that the 2009 dismemberment was missing the skull and was the first to suggest they might be from the same person! To date, the right and left forearms and hands, as well as the left and right legs from mid-thigh to the feet of this individual are unaccounted for.

After removal of the skull from the concrete, a facial impression was clearly visible in the cement. Under the forensic anthropologist’s supervision, a silicone material (Dragon Skin® 10 MED) was used to create a mold of the impression inside the concrete. Dragon Skin is a high-performance silicone rubber that can be used for a variety of applications ranging from movie special effects and skin effects to medical prosthetics, orthopedics, and cushioning applications. It is clear (pigment can be added for a desired color), can stretch and spring back to its shape without distortion, and is relatively inexpensive. The Dragon Skin comes in two thick liquid parts (parts A and B), which when mixed in equal parts together will cure chemically and solidify at room temperature. No measuring, calculations, or scales are needed. After mixing parts A and B, the forensic anthropologist poured the mixture into the concrete mound where the facial impressions were observed. Unfortunately, during this first attempt of making a mold of the inside of the concrete, small holes in the base of the concrete caused the Dragon Skin to leak out. Although the first attempt was not successful, the silicone from the first pour sealed all of the holes. The second attempt yielded a detailed 3D Dragon Skin rendering of the individual’s face and injuries after death, when the head was placed into the wet concrete (see Figure 4). The structure of the face was clear, and details such as lack of facial hair were noted (i.e., a beard or mustache, which cannot be deduced from the skeleton). The eyes and lips were closed; no teeth were visible. The trauma to the cranium was also visible in the mold, as well as possible swelling/injuries to the soft tissue of the face. No pigment had been added to the silicone upon mixing, so soil was rubbed onto the final mold to provide a color contrast which made features more visible.

Figure 4. Anterior (A) and right lateral (B) views of the silicone mold created from the concrete.

A forensic artist was able to create a two-dimensional forensic skull reconstruction in the blind based on the examination of the skull to corroborate identification (see Figure 5). A forensic skull reconstruction is an artistic and scientific approach to helping aid in the identification of human remains. Through the use of tissue depth markers, which are set in 21 anthropological landmarks, the face is built up to resemble what he/she may have looked like in life. The tissue depth markers are erasers cut by hand and glued onto the skull using Duco Cement. The first ten markers run down the middle of the face from the forehead to the chin. Markers 11–21 contain two sets, for either side of the face. These tissue depth markers represent the thickness of the muscles, tendons, and skin surface and act as a guideline for the topographic drawing. Once the tissue depth markers are glued on and set, a photograph is taken using a 1:1 scale, which is life size. A clear vellum paper is overlaid, and a drawing is done based on the photographed skull with adhering tissue depth markers underneath. This 2D technique was pioneered by Karen T. Taylor (Taylor, 2000).

Figure 5. The soft tissue depth markers on the skull placed by the forensic artist (A), a 2D drawing created by the forensic artist based on the tissue depth markers and the appearance of the face from the mold (B), and an overlay of the drawing and skull with tissue depth markers (C).

Overall, the multidisciplinary team of forensic scientists who worked on the skull in concrete were able to obtain as much information as possible from the skeletonized and fragmented remains. Positive identification was made ultimately with DNA technology, but other modalities such as dental evidence, the biological profile, a 3D silicone cast of a facial impression left in concrete, and the forensic skull reconstruction provided additional support to the DNA identification in the event that it was questioned in a court of law. The skeletal trauma on the cervical vertebrae was consistent with dismemberment. Sharp and blunt force trauma were caused by a sharp or beveled instrument using a hacking or chopping motion. Unfortunately, although this case is a homicide and the perpetrator is known, he will not be brought to justice unless he returns to the United States.

Lessons Learned

• A multidisciplinary approach to this case produced more information regarding the decedent and cause/manner of death than a single-field approach.

• Ancestry estimation using morphology and metrics can be challenging and sometimes contradictory; understanding the limits of anthropology methods, techniques, and databases for estimating ancestry is imperative. The morphological ancestry estimation was puzzling to the forensic anthropologist in this case because of the mix of morphological features and the low Fordisc typicalities. Low typicality values indicate that the reference sample for the unknown may not be in included in the comparative database. The decedent was from Pakistan, a population which is not represented in the Fordisc reference sample. Furthermore, individuals from Pakistan and other surrounding areas have morphological cranial features that do not always fall neatly into one of the three major ancestral designations (European [White], African [Black], and Asian).

• A mold-making silicone material, such as Dragon Skin, can be used to create 3D molds from impressions in concrete. The 3D molds can provide additional evidence in a case. A forensic artist also produced a 2D facial reproduction. While this case was identified via DNA, the facial mold and reconstruction would have been helpful in the absence of other available methods of positive identification and provided an additional line of support for the DNA identification.

Acknowledgments

The authors would like to thank the following individuals for their contributions to this interesting case: Dr. Michael Caplan, Detective Alfred Ciccotto, Robert Baumann, Joshua Denenberg, Danielle Gruttadaurio, Dr. David Lynn, Dr. Lillian Nawrocki, and Clyde Wells.

About the Authors

Kristen Hartnett-McCann is with the Office of the Chief Medical Examiner in Farmington, Connecticut. Ruth E. Kohlmeier is with the Suffolk County Office of the Medical Examiner in Hauppauge, New York.

About the Editors

Heather M. Garvin is currently an Associate Professor of Anatomy at Des Moines University, where she consults on forensic anthropology cases for the State of Iowa and continues human skeletal research. Natalie R. Langley is Associate Professor of Anatomy at Mayo Clinic College of Medicine and Science.

About this Title

Case Studies in Forensic Anthropology: Bonified Skeletons (1st Edition), now available from CRC Press, offers a set of unique case studies written by an international group of practicing forensic anthropologists. The text prepares students and professionals for the diverse range of cases and challenges they will encounter in the field.

References

Bass, W. M. (2005). Human osteology. Columbia, MO: Missouri Archaeological Society.

Buikstra, J. E., and D. H. Ubelaker. (1994). Standards for data collection from human skeletal remains. Proceedings of a seminar at the field Museum of Natural History (Arkansas Archeological Survey Research Series No. 44). Fayetteville, NC: Arkansas Archeological Survey.

Hefner, J. T. (2009). Cranial nonmetric variation and estimating ancestry. Journal of Forensic Sciences, 54(5), 985–995.

Jantz, R. L., & S.D. Ousley (2005). FORDISC 3: Computerized forensic discriminant functions (Version 3.1). Knoxville, TN: The University of Tennessee.

Rhine, S. (1990). Non-metric skull racing. In G. W. Gill, & S. Rhine (Eds.), Skeletal attribution of race, methods for forensic anthropology (pp. 9–20). Albuquerque, NM: Maxwell Museum of Anthropology.

Taylor, K. T. (2000). Forensic art and illustration. Boca Raton, FL: CRC Press.

Walker, P. L. (2008). Sexing skulls using discriminant function analysis of visually assessed traits. American Journal of Physical Anthropology, 136(1), 39–50.

This article appeared in the Winter 2019 issue of Evidence Technology Magazine.
Click here to read the full issue.

 
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