Tracking the route walked by Missing Persons and Fugitives: A Geoforensics casework (Italy)

1. Introduction

Since the 2001 September 11 attacks and the Global War on Terror, the organizational structures and procedures devoted to the search for persons of national and international interest assumed an important role in the global counterterrorism strategies [1,2].

In particular, criminal investigations, aimed to track the route walked by Missing Persons and Fugitives (MPFs) in the urban and rural territory, usually involve Intelligence analysts (IMINT - Imagery Intelligence, OSINT – Open Source Intelligence, etc.), military planners, experts in mobile forensics sniffer, dog handlers, and traditional investigative methods [1,3]. Notwithstanding, to track backwards the route traversed by the MPFs may be a very arduous task, when the MPFs do not bring with them mobiles, GPS or any other technological devices and they move in uninhabited rural areas of the countryside devoid of security or private tele cameras and covered by dense vegetation. In such peculiar circumstances, as demonstrated since the XVIII century [4,5,6] the mapping of the paths walked by the actors of crimes can be realized thanks to comparative analyses based on geological and soil evidence collected on the crime actors and the scenes of the events, respectively. In Germany, the study of the stains of stratified soil on the footwears and trousers of a homicide suspect allowed the expert Georg Popp to link him to a sequence of different sites of the crime scenes and suspect’s home [4]. Nowadays, once the MPFs are found, dead or alive, a very efficient backwards criminalistic approach may consist in comparing both the geological traces and micro traces found on the MPFs’ belongings (unknown samples, i.e. of unknown provenance) with soils/sediments and plants exposed in the sites of finding, last sighting, alibi, and investigative interest (known samples, i.e. of known provenance). A match of the comparative analysis data may demonstrate the provenance of the unknown traces from a site showing analogous microenvironmental characteristics [7].

With this in mind, the present research reports the scientific method and main results of geological comparative analyses, requested by the judicial authority for solving a “mediatic” forensic casework occurred in Italy in the countryside a few years ago. Geological data allowed tracking the route walked by the two MPFs revealing very useful information for the consequent criminological and criminalistic implications.

Notwithstanding the criminal proceeding was archived, the Author preferred to deal with the data and inferences described in the following, presenting MPFs/victims, samples, and sites in anonymously way.

3. Results on the Comparative Analyses

3.1. Geological Evidence

Samples resulted to be made of sandy to silty hyaline siliciclastic grains mainly composed of mono-mineral grains/clasts of quartz with different intensity yellow to orange Fe-coatings, minor opaque yellow ocher lithoclasts of quartzarenites, and microfossils (benthic foraminifera).

Mineralogical, petrographic, and sedimentological examinations on the geological trace and soil evidence revealed that these were mainly composed of an analogous mineral assemblage. Notwithstanding the mineralogical homogeneity, seven main classes of grain typologies were identified on the base of different mineralogical and textural characteristics and parameters (luster, coating, color, shape, habitus, roundness, and sphericity) examined under stereobinocular reflected and transmitted light microscope, scanning electron microscope with an energy dispersive (SEM-EDS) X-ray analyser for X-ray microanalyses.

Figure 3. Instrumentations. A) Laser diffraction granulometer (Malvern Instruments Mastersizer 2000). B). Workstation - Motorized stereomicroscope with reflected and transmitted polarized light (Zeiss Stereo Discovery.V20, on the left), motorized petrographic optical microscope with reflected and transmitted polarized light (Zeiss Imager.M2m mode, on the right), and image analysis software (Zeiss AXIOVISION, in the center) - Forensic Geology laboratory, MIFT Department, University of Messina. C) SEM (FEI QUANTA FEG 450 model) equipped with EDS system and workstation (AMETEK) - Laboratory of microscopic analyses, Engineering Department, University of Messina. Source: Author.

Figure 3. Instrumentations. A) Laser diffraction granulometer (Malvern Instruments Mastersizer 2000). B). Workstation - Motorized stereomicroscope with reflected and transmitted polarized light (Zeiss Stereo Discovery.V20, on the left), motorized petrographic optical microscope with reflected and transmitted polarized light (Zeiss Imager.M2m mode, on the right), and image analysis software (Zeiss AXIOVISION, in the center) - Forensic Geology laboratory, MIFT Department, University of Messina. C) SEM (FEI QUANTA FEG 450 model) equipped with EDS system and workstation (AMETEK) - Laboratory of microscopic analyses, Engineering Department, University of Messina. Source: Author.

The identified grain characteristics and parameters were described for each class. About one thousand of medium-fine to very fine sandy grains were analysed in the unknown samples as well as in the known samples, in the complex (Table 2, Figure 4).

Grains appeared mostly rounded with minor percentage of sub-angular clasts whereas the Riley sphericity resulted to be equal to 0.8 both in both the unknown and known samples.

Additional comparisons, accomplished in order to exclude possible previous traces in the victims’ questioned samples related to their staying with the same footwears in the sites visited in the days immediately before the tragic event, allowed to ascertain the absence of particles composed of mono- and polymineral assemblages of metamorphic rocks typical of the soils collected in these other locations of investigative interest.

Two (250-125 µ, 125-63 µ) and three (250-125 µ, 125-63 µ, <63 µ) grain sizes were identified as the most representative ones of both the unknown and known samples. The distribution of the quantitative data related to the seven class characteristics of the unknown and known samples, reported for both the 250-125 µ and the 125-63 µ grain sizes, showed an optimal overlaps and trends (Figure 5). In particular, three main classes were prevalent in both unknown and known samples. These were in order of abundance (Table 2, Figure 5):

i

ID06 - Rounded and spherical hyaline clasts with yellow/orange coating with a percentage of sub-angular and lamellar grains.

ii

ID02 - Rounded hyaline grains with evidence of the original crystalline habitus with yellow/orange coating.

iii

ID03 - Rounded and spherical hyaline grains without coating.

Figure 4. A-D) Microphotographs taken under stereobinocular microscope with reflected light of sandy grains of quarts. A) Unknown trace evidence observed with dark background. B) Known evidence observed with dark background. C) ID1-4 ID6 class grains of quarts observed with mm-sized background. D) SEM micrograph of unknown sample with ID02 class grain. E) SEM-EDS spectrum of quarts grain with Fe coating (spot 2 in Figure 4D). Source: Author.

Figure 4. A-D) Microphotographs taken under stereobinocular microscope with reflected light of sandy grains of quarts. A) Unknown trace evidence observed with dark background. B) Known evidence observed with dark background. C) ID1-4 ID6 class grains of quarts observed with mm-sized background. D) SEM micrograph of unknown sample with ID02 class grain. E) SEM-EDS spectrum of quarts grain with Fe coating (spot 2 in Figure 4D). Source: Author.

Figure 5. Comparisons of the percentages of the 7 class characteristics recognized in hundreds of unknown (red line) and known (green line) samples (from the event sites), reported for the 250-125 µm grain size (A) and the 125-63 µm grain size (B). Minimum, medium, and maximum values (horizontal traits) are also shown. Source: Author.

Figure 5. Comparisons of the percentages of the 7 class characteristics recognized in hundreds of unknown (red line) and known (green line) samples (from the event sites), reported for the 250-125 µm grain size (A) and the 125-63 µm grain size (B). Minimum, medium, and maximum values (horizontal traits) are also shown. Source: Author.

3.2. Botanical Evidence

Forensic botany was applied for the present casework in order to corroborate the forensic geology investigations. The amount of the vegetal material was prevailing on the inorganic grains. The vegetal fraction separated from the geological traces related to the unknown samples from the MPFs and their belongings and observed under stereomicroscopy, microscopy, and SEM-EDS system, resulted composed of plant fragments or entire elements of branches, twigs, leaves, thorns, capsules, fruits, seeds, pollen, herbaceous fragments, wood, vegetable debris, decomposing organic material (humus), and algae (including diatoms).

The main 12 species of remnants of traces of the identified terrestrial plants were [98]:

• Erica arborea (leaves, capsules, seeds).
• Quercus suber (leaves, flowers, seeds).
• Olea europaea (leaves, seeds).
• Cistus monspeliensis (leaves, seeds, capsules, etc.).
• Pistacia lentiscus (leaves, seeds).
• Myrtus communis (leaves, seeds).
• Cytisus infestus (branches, legume, thorns).
• Smilax aspera (leaves, thorns).
• Rosa sempervirens (thorns).
• Rubus ulmifolius (thorns).
• Rosacea Amygdaloidea (thorns).
• Cynara cardunculus (thorns).

Peculiar particles were considered the thorns and seeds being the most abundant vegetal component sampled on bodies, clothing, and footwears of both MPFs.

Over 522 seeds of Erica arborea and 81 thorns ascribable to Rosa sempervirens, Rubus ulmifolius, Rosacea Amygdaloidea, Cynara cardunculus, Cytisus infestus, and Smilax aspera were found in the shoes of victim 1, mostly inside the shoes and planted on the soles, respectively. Another peculiar material was represented by an aggregate made up of remnants of freshwater algae found in the sole of one victim 1’s footwear [98].

Only 16 thorns ascribable to Rosa sempervirens or Rubus ulmifolius, Cynara cardunculus, Cytisus infestus, and Smilax aspera were found planted on the soles of the shoes of victim 2. No traces of algae were found except a unique diatom [97,98].

The same 12 species of terrestrial plants above reported were also found in the vegetation present in the sites of the events and in the vegetal component of the soils collected from this area.

On the base of the above, four main macro-areas with different botanical characteristics were distinguished during remote sensing and field work. The identified macro-areas were [98]:

• Shrub formation with Mediterranean maquis (prevailing macro area).
• Area inside the highway perimeter.
• Meadow area with anthropic pressure from pasture with some puddles of freshwater with algae.
• Tree formation dominated by Sughera (Quercus suber L.) with a circumscribed zone showing abundant concentration of Erica arborea shrubs wood and soils rich in fresh to decomposed seeds of Erica arborea (about 6000 seeds of Erica arborea were examined and counted in the soils).

3.3. Tracing the Route Walked by the Two MPFs

During investigations, great attention was also devoted to the specific search for rare or peculiar particles or assemblages of inorganic and vegetal origin. This examen allowed to recognize in the unknown samples:

• Rare particles of calcite and dolomite.
• Peculiar compositions of clay minerals rich in calcium phosphate.
• Peculiar assemblages of different classes of mineral grains.
• Vegetal remains of mm-sized thorns of Cynara cardunculus and Rosa sempervirens, seeds of Erica arborea, and assemblages of algae.

The same rare and peculiar materials were also recognized in some specific sites of the scene of events, as specified in the following. Geobotanic data on the unknown samples resulted to be typical of microenvironments very similar to those identified in the scene of events. These results were of paramount importance in allowing investigators and judicial authority to link the MPFs to specific sites of the scene of events and in tracing the route of both the MPFs, obtained from 9 specific microenvironments recognized in the scene of events. Figure 6 and Table 3 illustrate the sequence and distribution of the match points and match linear belts (M), from which the path was delineated by means interpolation of matching sites and 4 exit/entry points (E1-4), recognized in the event scene, starting from the site of the car accident site (CA). The localizations of the two different finding sites of the human remains (F1 and F2) were also reported.

3.3.1. Car Accident (Table 3, Figure 6)

The car accident occurred among two vehicles inside a tunnel of the highway. After the crash, the two subjects abandoned their vehicle and went out of the tunnel, reaching a lateral gate of the highway.

3.3.2. Match Point 1 (M1) (Table 3, Figure 6)

Inorganic micro traces (calcite) from MPF 1’s ring.

These micro traces were comparable with the calcareous composition of the top of a ~ 1 m high perimeter wall delimiting the lateral gate of the highway (Figure 7). The transfer from the wall to the ring could realize when the MPF 1, in order to reach the raised ground on the back of the highway, passed on the wall touching it with the hands to lift him-herself from the roadway in order to continue to escape from the car accident site.

3.3.3. Exit (E1) (Table 3, Figure 6)

Two MPFs passed through a rudimental wood gate delimiting the area surrounding the highway tunnels.

3.3.4. Match Linear Belt 2 (M2) (Table 3, Figure 6)

Organic traces (thorns of Cynara cardunculus) from MPF 1’s sock and MPF 2’s shoes.

This evidence was comparable with some thorny plants growing on an uncultivated field in the meadow area with anthropic pressure from pasture (Figure 8). The transfer from the plants to the shoes could realize when the subject walked on these thorny plants distributed in the linear belt reported in Figure 6.

3.3.5. Match Point 3 (M3) (Table 3, Figure 6)

Organic traces (algae) from MPF 1’s shoes.

These were comparable with algae present on freshwaters of a muddy puddle (Figure 9). The transfer from the puddle to the shoes’ soles could realize when the subject walked on this specific puddle.

3.3.6. Match Point 4 (M4) (Table 3, Figure 6)

Inorganic micro traces of P-rich clays from MPFs’ shoes.

These were comparable with a wet soil present on the above reported muddy puddle (Figure 10). The transfer from the P-rich clayish wet soil to the victim could realize when the MPF 1 and 2’s shoes walked on the wet area.

3.3.7. Match Point 5 (M5) (Table 3, Figure 6)

Inorganic traces from MPF 2’s shoes.

This particle assemblage was comparable with the sandy and silty soil present in a specific site of an uncultivated field in the meadow area with anthropic pressure from pasture (Figure 11). The transfer of the soil to the shoes could realize when the victim walked on this site.

3.3.8. Exit Point (E2) (Table 3, Figure 6)

The two MPFs passed through a rudimental wood gate delimiting an uncultivated field in the meadow area with anthropic pressure from pasture.

3.3.9. Match Point 6 (M6) (Table 3, Figure 6)

Inorganic traces (dolomite) from MPF 2’s shoes.

These were comparable with clasts of pinkish dolostones artificially reported on a dirt road present on an uncultivated field, near a wood rudimentary gate (Figure 12). The transfer to the shoes could realize when the victim walked on this road.

3.3.10. Entry Point (E3) (Table 3, Figure 6)

The two MPFs passed through a passage in the barbed wire delimiting the Sughera wood with Erica arborea plants, entering in this cover and isolated area.

3.3.11. Match Linear Belt 7 (M7) (Table 3, Figure 6)

Organic traces (Erica arborea seeds) from MPF 1’s shoes (Figure 13) and socks.

The freshness state of the Erica arborea seeds in the MPF 1’s shoes (Figure 13A) were comparable with seeds present in the soil present in the wood with Sughera (Quercus suber L.) associated with Erica arborea shrubs above cited (Figure 13). The transfer to the internal parts of shoes and socks could realize when the victim walked on this area, along the identified linear belt, infilling the shoe internal parts with Erica arborea seed-rich soil and seeds fallen by the shrubs due to the impact of the body with Erica arborea shrubs.

3.3.12. Match Point 8 (M8) (Table 3, Figure 6)

Inorganic traces from MPF 1’s shoes.

This particle assemblage was comparable with the sandy and silty soil present in the area of the wood with Sughera (Quercus suber L.) and Erica arborea shrubs (Figure 14). The transfer of the soil to the shoes could realize when the MPF1 passed on this area.

3.3.13. Finding Site (F2) (Table 3, Figure 6)

The skeletonized human remains of victim 2 were found distributed in an articulated area of the dense Mediterranean maquis.

3.3.14. Exit (E4) (Table 3, Figure 6)

The MPF 1 passed through a passage in the barbed wire delimiting the Sughera wood with Erica arborea plants, abandoning this area.

3.3.15. Match Point 9 (M9) (Table 3, Figure 6)

Organic traces (Rosa sempervirens thorns) from MPF 1’s shoes, socks, and clothing.

These traces were comparable with the thorns of the climbing Rosa sempervirens plants growing on the infrastructure in proximity of the finding site of the corpse (Figure 15). The transfer to the victim belongings could realize when the subject climbed on this structure (M9 in Figure 6).

3.3.16. Finding Site (F1) (Table 3, Figure 6)

The manner of death of the MPF 1 for precipitation was ascertained by the medico legal investigations. The prone position of the MPF 1’s body, its distance from the infrastructure, as well as its relationships with the plants present on the ground univocally supported this reconstruction. In particular, the injuries on the posterior and lateral sides of the limbs could be dependent on a dynamic impact due to the body’s precipitation on the plants growing on the ground.

4. Discussion and Conclusions

The wide spectrum of mineralogical, morphological, morphoscopic, textural, and botanical determinations accomplished for the present criminal case work allowed to ascertain a general high degree of compatibility among samples collected on the MPFs and on the scene of events, and the exclusion of possible previous traces related to their staying with the same footwears in other sites in the days immediately before the tragic event.

These comparative analyses provided fundamental info-investigative data of paramount importance for establishing the active pre-mortem presence of the MPFs on the scene, dealing with a criminal case where other methods were not very useful and inapplicable. Nobody saw the MPFs walking in the countryside, MPFs had not any mobiles, GPS, or technological devices, no tele cameras were in the scene.

The most significant positive matches, based on the finding of peculiar and rare particles and assemblages, allowed reconstructing a very detailed walking carried out by the two MPFs on the event site. As a matter of facts, the finding of a ten of different points and linear belts of positive match, from 1 (near the car accident site) to 9 (site of the finding of victim 1), allowed to reconstruct and tracking the route walked by the two MPFs in the hours immediately preceding their death (Table 3, Figure 6).

These inferences were very useful for the judicial system. A few criminological and criminalistic inferences based on the investigations, carried out in laboratory and on field, allowed to hypothesize that:

• Both MPFs actively interacted with the natural and anthropogenic microenvironments recognized in the scene of events (Figure 6).
• Both MPFs actively walked in the scene of events along a specific route stretched in areas with different degrees of vegetation density and difficulty to pass through (Figure 6).
• MPF 2 walked for a shorter path than that of MGF 1; this path was reconstructed up to the dirty path with detritus of dolostones (M6); it may be hypothesized that MPF 2 was carried out in the MPF 1’s arms in the Sughera woody area with Erica arborea, from the surrounding of M6 site up to M8 site, i.e. in an area very next to the site of finding of victim 2 (F2 in Figure 6).
• MPF 1 walked for a longer path than that of MPF 2 up to the site of finding of the body (F1 in Figure 6).
• MPF 1 actively climbed on the infrastructure (M9 in Figure 6). This action supported evaluations made by the coroner on injuries due to precipitation from a high infrastructure.

In conclusion, the peculiar and rare grains, minerals, composition, textures together the peculiar and rare assemblages analysed in the unknown and known specimens from victims and event scene permitted to identify a “fingerprint” of most of the examined specimens. Most of these fingerprints were obtained by means of image analysis and the manual counting of grain characteristics. This procedure, also if it was extremely time consuming and relevant only in cases after the MPF’s finding, it was of uttermost importance in strengthen the reconstructions here proposed. In such way, investigators revealed to be able to provide very strong geological and botanical evidence for supporting criminal investigations.

The here presented method for tracking the route walked by MPFs could fall back in the strategies to contrast the Al-Qaeda terrorism. When a terrorist is captured in the countryside, it may be useful or necessary to track backwards the route walked by him/her to search for a terrorist den or a site of investigative interest (burial of firearms, explosives, etc.).

Notwithstanding these encouraging and promising results and the great potentiality of this method, in Italy Forensic Geology still represents a minor discipline of the Forensic Sciences [104]. In the Italian police criminal laboratories, the analysis of geological and botanical traces actually rarely occurs, differently from the realities of other countries (Federal Bureau of Investigation -FBI- Laboratory of Trace Evidence, Quantico, USA [51,105]; Institute of Criminalistics -ICP- Prague, Czech Republic [106,107]; Australia [50]).

On the basis of the above, for the next generations of forensic experts in geology and botany, it should be desirable that the academics and researchers:

• Further implement scientific and didactic initiatives on Forensic Geology and Botany [108,109,110,111,112,113].
• Promote initiatives for introducing the master’s degree in geology in the police applications for assuming Geologists/Forensic Examiners for the police forensic bureau (Carabinieri, Police).
• Develop forensic protocols envisaging all possible technical procedures / operations to accurately apply on the crime or event scene to preserve evidence made of inorganic and organic materials and strengthen greater interaction and collaboration between forensic geologists, botanists, and experts in legal medicine directly on the crime scene, to arrange all the activities aimed at preserving these traces as far as possible, even during necropsy operations.