How police fight crime with DNA - TechCentral

How police fight crime with DNA

Retired New York Police Department detective-sergeant Joe Blozis

Pretoria and Cape Town are home to two of the most advanced forensic laboratories in the world, but the biggest limitation to their efficacy is the lack of a national and standardised DNA database.

Major-general Adeline Shezi of the South African Police Service’s forensic services division says the country has been talking about creating a DNA database for the past five years but discussions are ongoing and that all interest groups have to be heard. The most frequently raised concern relates to privacy, but most databases are designed keep personal information hidden.

One of the most widely used standards for forensic databases is known as Codis (Combined DNA Indexing System). This is the database management system used in most of the US and Europe. Although 44 nations have DNA databases, only the European Union has agreements in place whereby member states must give each other access. Shezi says South Africa has yet to settle on a standard for its proposed database.

Retired detective-sergeant Joe Blozis, who worked in the New York Police Department, says all crime scenes are processed in similar ways around the world, with documenting the scene and collecting evidence being the most important.

Blozis says that although DNA analysis has been possible since the mid-1990s, it is only in the past decade that it has come into its own. “All biological evidence is important,” he says. “It has to be packaged in paper so it can breathe. Genetic material decays in a closed environment, so you can’t use plastic.”

According to Blozis, DNA is more than just a powerful law-enforcement tool. “It’s the fingerprint of the 21st century.”

He says America’s DNA database is growing daily and isn’t only useful for linking criminals to current crimes, but can be used to examine old cases, “as long as the evidence was packaged properly”. Moreover, it can be used to exonerate the innocent.

US$1 spent on DNA analysis saves an estimated $90 on other expenses, according to Blozis.

Arthur Eisenberg, co-director of the Institute for Applied Genetics in Texas, says there’s a great deal of value to be had from countries sharing databases, but many are reluctant to do so. Another use for DNA databases is in “familial searching”, where a database may lead to a relative of a suspect whose DNA has been collected from a crime scene.

Crime fighter

“As the database grows, you can find similar samples and these can be used as investigative leads,” says Eisenberg. “Perhaps the most well-known case of familial searching was that of the ‘Grim Sleeper’ who murdered and raped in the 1980s and 2000s. He was caught because his son committed a crime that saw his DNA sample entered into the database.

“He was identified as a possible family member of the Grim Sleeper. The police followed the boy’s father, who ordered a pizza in a restaurant and didn’t eat the crusts. The police collected these and, thanks to DNA tests, were able to link him to the crimes.”

Eisenberg says that originally, DNA was only collected for violent crimes or other crimes that resulted in arrest and prosecution. However, this has been extended to property crimes like burglary because there have been sufficient instances where processing burglars has resulted in them being linked to DNA collected from other violent crimes. “We’ve picked up people for a break-in who’ve turned out to have murdered and raped.”

A study in Chicago tracked eight criminals who committed a large number of crimes and found that, had DNA analysis been available, dozens of crimes could have been prevented. “Criminals escalate their activities,” Eisenberg says. “If you get these individuals early in their careers, you can stop them. You can’t save the first victim, but you can hopefully save others.”

South African database
Shezi says the South African Police Service is “very supportive” of the idea of creating a DNA database because it sees the value that it can offer in terms of crime prevention. “But there are political considerations and concerns,” she says. “People want to know what we’re going to do with that information now and in future, how long we need to store it, and how we can guarantee it won’t be abused?”

Legislation is needed to standardise DNA collection, classification and the rules around analysis, says Shezi. In addition to the two sites in Pretoria and Cape Town, she says police are planning to build laboratories in Port Elizabeth and Durban in coming years.

“It’s difficult to find the right skills,” Shezi says. “South Africa doesn’t have the necessary courses at its tertiary institutions. We recruit graduates and do the training ourselves.”

South Africa has 841 forensic analysts working in laboratories, and more than a thousand forensic experts who work at crime scenes. Shezi suggests the country has the requisite resources; what it needs now is legislation from government to ensure these resources are properly used.  — (c) 2012 NewsCentral Media

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