Photographic superimposition of digital images resulted in the
positive identification of a "disappeared" Chilean national
found in the Republic of Panama. Comparisons of antemortem and postmortem
images of fragmentary skeletal remains that had been buried since
1977 were performed using an IBM-compatible computer and Adobe Photoshop
Photographic superimposition is useful when the remains are likely
to belong to a particular missing person, and photographs are available
(Ubelaker 2000; Ubelaker et. al. 1992). Generally, this technique
is best used for exclusion, but a positive identification is possible
if the morphological features are unique (Ubelaker 2000).
The methods for comparison of antemortem photographs to human skeletal remains
have ranged in complexity from the relatively simple approach of using photographic
comparisons, to more complex use of video-mediated methods (Matsui 2001). All
of these methods necessitate the use of complete skulls for comparison, which
may not always be available. This case report presents the utility of using digital
images in the positive identification of fragmentary skeletal remains using a
method described by Matsui (2001).
On November 15, 2003, the forensic anthropology team for the Panamanian Truth
Commission flew by helicopter to the island of Coiba, the largest island in the
Mesoamerican Pacific. The island is located 24km offshore from Panama and is separated
from the mainland on the east by the Gulf of Montijo and on the northwest by the
Gulf of Chiriqui. The island's first inhabitants were indigenous groups dating
to 500 BC, who were expelled from the island by Spanish conquistadors sometime
in the early part of the 16th century. It was soon abandoned by the Spaniards
and was only reinhabited in 1914 when it became a penitentiary, which currently
holds approximately 100 inmates.
The Panamanian Truth Commission's directive is to investigate the
deaths and disappearances by the military regimes of Generals Torrijos
(1968-1978) and Noriega (1983-1989). On this mission, the forensic
anthropology team went to the Maranon Cemetery, which is situated
at the central encampment of the penal colony, to verify information
provided by informants as to the possible location of the graves
of a Panamanian and a Chilean who disappeared in 1977. Because of
this testimony, four burials were exhumed and their contents analyzed.
Basic antemortem biological information was provided for both individuals.
The Panamanian, Cecilio Hazlewood, was predominantly of African
ancestry, whereas the Chilean, Gerardo Olivares, had typical Andean
features (indigenous) and, in particular, unique nasal bone morphology.
The contents of the burials were examined in situ, and two of the
burials were determined to be more recent than the late 1970s due
to their state of preservation. They were thus discarded as possibilities.
The state of preservation of the two remaining burials was consistent
with burials from the 1970s. One grave contained the remains of
an individual of predominantly African ancestry consistent with
the general population of Panama. However, burial T-116 contained
the remains of an individual of predominantly indigenous ancestry
and notably not of Central American or African origin. In addition,
this individual had unique nasal bone morphology also consistent
with the antemortem biological information provided for the Chilean.
The skeletal remains from burial T-116 are in a relatively good
state of preservation with some root activity, such as surface erosion
and root growth around and within some of the skeletal elements.
However, many of the more fragile elements composed of predominantly
cancellous bone, such as vertebrae, ribs, pelvis, and long bone
epiphyses, are completely fragmentary. Two shirts were bundled and
placed adjacent to the skull (occipital portion) on the left side.
One shirt was orange and the other was white with blue anchors.
Both were 1970s-style with large, pointed collars. This individual
was also wearing a pair of red trousers. Based on the condition
of the remains and the style of clothing, this burial is most likely
post-1970 (Figure 1).
Figure 1. Photograph of Burial T-116
Morphological characteristics of the cranium (prominent supraorbital
ridges, rugose nuchal area, blunt supraorbital margins, and square
chin) and metric analysis (femur midshaft diameter, Black 1978)
indicate that this individual is male.
The remains represent an individual in young adulthood (20-34 years).
The remains do not exhibit evidence of osteoarthritis or other degenerative
changes. Based on the overall degree of skeletal degeneration, this
individual is more likely in his 20s to early 30s. The fragmentary
nature of the remains prevents a more precise determination of age.
Ancestry was assessed by gross cranial morphology. Craniofacial
features (broad face, nasal overgrowth, projecting zygomatics, blurred
nasal sill, large teeth, and edge-to-edge bite) are characteristic
of an individual of indigenous ancestry, and notably not of African
origin (Bass 1995; Krogman and Iscan 1986; Rhine 1990).
The maximum radial length (236mm) was used to estimate stature.
Generally, upper limb bones should not be used to estimate stature
as evidenced by the larger standard deviations; however, the left
radius was the only complete long bone available. The predictive
stature equation for Mexican males (more appropriate for an indigenous
individual) derived by Trotter (1970) was used. The predicted stature
is 164.5cm +/- 4.04cm with a 95 percent prediction interval of 156.4-172.6cm.
This individual exhibits unique nasal bone morphology. The nasal
bones project from the skull at approximately a 90-degree angle.
This individual also has a deviated nasal septum, which encroaches
into the left nasal cavity.
These remains are consistent with the antemortem biological information
provided for Gerardo Olivares.
Who was Gerardo Olivares?
In 1969 after Gerardo Olivares finished mandatory military enlistment
in the Chilean Navy, he went to the Chiriqui region of Panama
where he joined forces with, and was to become second in command
of, the guerillas opposing the military regime. He was detained
in 1972 and spent time in various prisons around Panama until finally
being sentenced to Coiba.
Last year a letter addressed to the Head of State of the National
Guard (or military junta) dated in the year 1977 was discovered.
According to this letter, the detainee, Gerardo Olivares, was shot
several times while attempting to escape.
A scanned antemortem black-and-white photograph of Gerardo Olivares
and his sister was provided for comparison (Figure 2). Because the
remains were interred for an extended period, the skull was fragmentary.
However, some unique facial features remained intact that allowed
comparisons to be made (Figures 3 and 4). The digital superimposition
was performed using an IBM-compatible computer and the software,
Adobe Photoshop 6.0. The postmortem images were taken in the field
using a Sony Cyber-shot model DSC-F717 digital camera. An important
caveat is to avoid artificial or unintentional manipulation of digital
images such as stretching to resize images (Matsui 2001).
Figure 2. Original Black-and-White Photograph of Gerardo
Olivares and his Sister
Figure 3. Photograph Taken in the Field of the Lateral
Aspect of the Nasal Bone Illustrating the Unique Nasal Bone Morphology
Figure 4. Frontal or Anterior of the Same Cranial Fragment
First, Gerardo Olivares was cropped
from the antemortem image (Figure 5). Second, the background was removed
from the postmortem image in the anterior view (Figure 6). Next, the postmortem
image was scaled and rotated to fit the facial angle observed in the antemortem
image. Finally, the digital image of the skull was overlaid onto the antemortem
image, which remained in the background. The image of the skull was then
moved to properly align the anatomical structures using the "hand tool" (Figure
Anatomical consistency was examined for glabella, nasal bone morphology,
shape of the eye orbit, and zygomatic or cheek bone. Significant
anatomical consistencies were observed in the antemortem and postmortem
images, and the remains could not be ruled out as those belonging
to Gerardo Olivares. In addition, the uniqueness of the nasal bone
morphology and glabella are consistent with known morphological
features for Olivares and are compelling enough to allow a positive
Figure 5. Cropped Image of Gerardo Olivares
Figure 6. Frontal or Anterior of the Same Cranial Fragment
after the Background Was "Erased" Using Photoshop
Figure 7. Superimposition or Overlay of the Skull onto
the Image of Olivares Showing Anatomical Matches
This case illustrates how modern computer imaging software can
be used in the photographic superimposition of fragmentary skeletal
remains. In particular, this method can be useful in cases when
there are limited resources, and when more expensive and rigorous
methods for positive identifications, such as mtDNA, are not a feasible
The author would like to thank Mr. Gary Knight, City-County Bureau
of Identification, Raleigh, North Carolina, for his technical support
during the initial phase of the superimposition.
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