Forensic Geology and the Murder-case of Aldo Moro

Rome, March 16, 1978 a car of the type Fiat 128 suddenly braked midst of the street, prompting the following cars to crash onto it. A series of shots from a machine-gun followed, killing all of the five bodyguards of Italian prime minister Aldo Moro. The prime minister was kidnapped, days later the first messages from the Brigate-Rosse, a terrorist-association active at the time in Italy, arrived, causing a severe political crisis as the government was insecure how to deal with the terrorists demands. Time passed, letters and messages were exchanged, when on May 8, an anonymous telephone-call signaled a parked car of the type Renault 4 in the center of Rome. 

 

Fig.1. Moro, photographed during his kidnapping by the Red Brigades.

Inside the car the Police found Aldo Moro, killed by a series of gunshots. Investigators immediately started to collect crime-scene evidence. During the autopsy small traces of sand were found inside Moro´s trouser cuffs, traces of geological material were also collected from the shoes and the trunk of the car, where the body was found. The forensic geologist had to answer two important questions: – could the geological evidence be tracked back to the site, where Moro was killed or his body dumped into the car? - could the geological evidence suggest an approximately time for when this happened?

The chemical composition of the sand grains was analyzed, so to may be able to identify the rocks from where the grains eroded. The grain-shape and -size distribution could help to identify the depositional environment of the sand. All the sand, from Moro´s clothing as from the interior of the car, was identical, suggesting that the body was dumped into the car where Moro was killed or at least imprisoned. It was loose sand, without cement between the single grains (so it was clear that it was not derived from an older sandstone), of uniform grain-size, very well sorted. The grains where also smoothed and rounded by constant abrasion, like it happens by the constant motion of waves. It was so easy to identify the material as recent beach sand. This identification was supported by the presence of marine shells and microfossils. The remains of marine organisms, living in shallow water, suggested that Moro was killed or imprisoned during his last days somewhere along the coastline near Rome.
The microfossils where identified as Miocene species, eroded from rock-outcrops not found along the coastline and transported by a river to the sea. This was an important discovery, as it suggested that the supposed crime-site was located near the delta of the river Tiber, the only river with a drainage basin where Miocene rocks were found. Also some grains of igneous rocks, recovered from the shoes, and eroded and transported from the volcanic hills surrounding the city of Rome, supported this hypothesis. Subsequent sampling showed that sand from an 11km long segment, situated north of the mouth of the Tiber, matched the sand found on Moro´s clothing. 

 

Fig.2. Geological map showing the Tiber-delta and the volcanic cones of the Alban Hills, from “Carta Geologica per servire alla storia dei Vulcani del Lazio del Prof. Giuseppe Ponzi” (1874), from the collection of the Italian Geological Service, published September 5, 2014 on the blog http://www.geoitaliani.it. The coastline of the Italian province of Latium is characterized by sedimentary rocks and recent river and marine deposits. The inland is formed by volcanic rocks, dated to the Pliocene.

There were only few streets in this area and indeed traces of asphalt were found on the tires of the car. However more careful analysis reveled that the asphalt was of very poor quality and comparison with sand-samples revealed that it was in fact unrefined bitumen, derived from the pollution of a nearby oil-tanker terminal, washed ashore and mixed into the sand. Traces of this kind of bitumen were then found also inside the car, Moro´s kidnappers  walked on the contaminated sand not long before the car was found, as the smears of bitumen were still fresh. This last observation suggested that Moro was killed shortly before the telephone-call and the discovery of the body.

More close investigation showed that on the shoes, below the layer of beach sand, there was also a layer of volcanic soil. Applying the principle of sedimentary superposition (as the soil-layer is covered by the sand, it must be older), the forensic geologists suggested that Moro was imprisoned, before being relocated to the shore, somewhere inland, may south-east of Rome, where on easily erodible volcanic rocks clay-rich soils formed over time. Pollen grains supported this reconstruction, as the pollen in the soil came from Cypress and Hazel, blooming late in winter, but there was no trace of plants blooming in early spring (after March-April, so Moro the last weeks before his murder couldn´t been there). Only years later the investigators found an apartment, in the south-eastern suburbs of Rome, where Moro probably was hold captive for some time.

Various suspected murders were arrested during a raid against the Brigate Rosse. Based on various partial confessions the crime was reconstructed as follows:

The bodyguards were killed by a commando, hiding along the street where another terrorist blocked with his car Moro´s convoy. Moro was then kidnapped and hold captive for 55 days in the anonymous apartment near Rome, where he was finally forced into the trunk of the car and executed. The car was then parked in the center of Rome and a kidnapper called the police.

But what about the found beach sand? The kidnappers claimed to have tried to mislead the investigators by faking evidence, pouring some saltwater and sand onto the victim and into the car. However to fake all the traces found on the car (especially the smears of bitumen) and on Moro´s shoes all those object had to be there on the shore – why such efforts to create evidence most people wouldn´t even realize exist? 
The supposed prison along the coastline was never found. Are the kidnappers with their misstatements hiding something, maybe a land property on the shore belonging to an important person? 
After five lengthy court proceedings and more than 37 years later still many questions remain unanswered...

Bibliography.

LOMBARDI, G. (1999): The contribution of forensic Geology and other Trace Evidence Analysis to the Investigation of the Killing of Italian Prime Minister Aldo Moro. J. Forensic Sci. Vol.44(3): 634-642