Tag Archives: DNA evidence

Hunting Burglars with DNA Tests

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DNA

Source: Office of Biological and Environmental Research of the U.S. Department of Energy Office of Science. science.energy.gov/ber.

Forensic DNA analysis is usually cast as an important tool for the investigation of a violent crime. However, investigators also use the technology to solve property thefts.

The September-October 2012 issue of Evidence Technology Magazine features an article by Joseph Blozis on “Using DNA to Fight Property Crime.” He explains how New York City’s Biotracks program demonstrated this new use of DNA testing. The NYPD recovered DNA samples from burglary cases with no suspects and forwarded the samples to private companies for analysis. The Office of the Chief Medical Examiner Biological Laboratory then uploaded DNA profiles to the FBI’s CODIS system. Eventually, the efforts led to the identification of burglars in no-suspect cases and established links between apparently unrelated burglaries.

The successes of the NYPD program and similar programs in other jurisdictions have proven the value of DNA testing to solve property crimes. Finding the funds and staff to run extra DNA tests is another challenge.

Tricks for Obtaining DNA

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DNA

 

In the Law & Order: LA episode, “Ballona Creek,” Detective Tomas Jaruszalski picks up a suspect’s discarded cigarette butt for DNA analysis. This type of surreptitious DNA collection is so common in fiction, that the practice doesn’t even merit a raised eyebrow. In real life, surreptitious DNA collection sparks protests from members of the public. At the same time, law enforcement agencies argue that the practice is justified, because an individual has no privacy interest in an abandoned DNA sample.

Instead of retrieving an abandoned item for DNA, law enforcement officials sometimes trick a suspect into giving up a DNA sample. In a case reported in 2009, police sent a letter about a class action lawsuit to a suspect. Eager to join the case, the suspect signed a form and mailed it in a self-addressed envelope. Investigators extracted DNA from the saliva on the envelope flap and found a match to a semen sample gathered from a 1982 rape-killing.

More recently, ABC News reported a recent success for a case concerning the 1976 killing a 70-year-old woman. During a recent review of the cold case, investigators obtained DNA from the old evidence.

The police had a suspect, now they needed the suspect’s DNA to check against the evidence DNA. So, they used a phony “gum chewing survey” and got their saliva sample from the suspect. The results led to an arrest.

An Expert’s View on DNA Evidence

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Finding DNA

 

NPR recently posted an interesting story entitled “Analysing The Evidence On DNA.” Ira Flatow interviewed Greg Hampikian, Director of the Idaho Innocence Project, about the uses and abuses of DNA evidence. The topics that they discussed include:

  • problems with DNA evidence collection,
  • advantages and disadvantages of the high sensitivity of modern DNA analysis,
  • use of DNA evidence in investigations, and
  • myths about evidence analysis perpetuated by TV shows.

The interview is definitely worth a look (or a listen).

Dealing with DNA Evidence

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DNA in a bottle

Source: U.S. Department of Energy Genomic Science program.

In his book, The Blooding (1989), Joseph Wambaugh described the first use of DNA testing in a criminal investigation. As it turned out, the new type of forensic analysis unveiled a rapist-killer in an unusual way. The police collected blood samples for DNA testing from every male between the ages of 16 and 34, living in the vicinity of the crime scenes. To dodge the test, a cake decorator named Colin Pitchfork paid a coworker to donate blood for Pitchfork. After the police learned about the ruse, they arrested Pitchfork, who confessed to the crimes.

Since then, DNA testing has become routine in both criminal and civil cases. Readers of mystery and crime fiction expect DNA analysis to play some role in a story set in modern times. One good source for basic information on DNA testing is the U.S. Department of Justice’s DNA for the Defense Bar. As the title indicates, the guide is particularly useful if your main character is a defense attorney who must confront damaging DNA evidence. The book is available at the National Institute of Justice website.