How soil could be key to catching criminals

A soil sample the size of a fingertip can be enough to catch a killer, which is why police are cataloging the different types in the UAE.

Colonel Abdulrahman al Hammadi of the Abu Dhabi Police says residue from the ground can show where a crime took place.

ABU DHABI // Soil, experts say, can tell many stories. And in the UAE, it can even solve crimes. A soil's colour, texture and mineral composition can speak to an area's geological past, while the tiny remains of organic matter or fossils can point to plants and animals that once inhabited the area.

Increasingly, such information is used as evidence in serious crimes such as murder, rape and large-scale theft, where it allows investigators to link a suspect with a crime scene or even to reconstruct a sequence of events. Col Abdulrahman al Hammadi, manager of the forensics evidence department of Abu Dhabi police, said police are preparing a database of soil in the UAE and its neighbouring countries. The process began with a survey of soil in Abu Dhabi, prepared by the Environment Agency - Abu Dhabi.

"The database will help in solving crimes because in any crime, soil and residue from the ground of the scene ends up on the person involved or on the victim, allowing investigators to determine where the crime had taken place," he said. "For example, soil from the crime scene can stick to a victim or criminal's clothes, shoes or hair, and if a body is transported from one place to another, so we can decide where the person was killed by matching up soil samples to the database."

It can also help police determine the route of a killer if he moved from one emirate to another, he said, by analysing soil's concentration, distribution and make-up. "Soil is actually very good evidence," said Dr Raymond Murray, a forensic geologist based in the United States. "It is good evidence because of the different types of things you can find in soil." Sometimes the combination will be unique, showing with certainty that two samples share the same origin. The samples need not be large to yield important results.

"I have just seen a case in which the man actually washed his shoes but failed to remove a bit of soil on one of them," he said. "He killed his girlfriend with a broken Coca-Cola bottle." The speck of soil used as evidence was "the size of the end of a fingernail", Dr Murray said. However, because of the presence of some unique particles and glass in the sample, it matched the crime scene. "There was a lot of luck in that case," he said.

Cases in the UAE have been cracked using such analysis as well. In one instance, a woman who murdered her husband had lured him to a location in the desert far from their home and killed him there before dumping the body near the house, Col al Hammadi said. But investigators found soil in the victim's shoes that was different from that in the area where they live, leading to a break in the case. "The database will also help in identifying where drugs were planted to know where [they] came from," he added.

The database will include information on pollen and water. Abu Dhabi Police had contacted oil companies to ask them for any soil samples they had collected before discovering that the Environment Agencty - Abu Dhabi already had been conducting soil surveys, which quickened the pace of the project. It will be finished in the next year, officials said. Razan al Mubarak, the environment agency's assistant secretary general, said such surveys have become standard practice.

"Almost all GCC countries have already undertaken soil surveys; the Kingdom of Saudi Arabia completed one in 1985, the Sultanate of Oman in 1990, Kuwait in 1999, and Qatar in 2005," he said. "The data provided can keep the police up to date with Abu Dhabi's geological patterns by studying its biological and mineral contents. "Soil evidence can be used to solve a number of cases, from murders, property damage, and theft to the illegal hunting of animals."

Although to the naked eye it might look homogenous, soil is actually made up of many different elements and substances. There are organic particles such as remains of dead animals or plants, as well as inorganic particles - tiny bits of rock and minerals. Soil can also contains tiny pieces of fibre, glass, paint, hair and many other materials. When examining a soil sample, forensic geologists first look at the colour, size and distribution of various particles. The next step is identifying a sample's mineral content and then looking for any unusual particles. The more unusual particles that are present in a sample, such as traces of rare minerals or pollutants, the more valuable it is as evidence.

* The National