Tag: forensic science

News Roundup: Real-Life Blood Spatter Analysis Catches Up to “Dexter”

By Andrew Moseman | March 1, 2011 2:55 pm

  • Materials violence: NASA will use a million pounds of force to crush a 20-foot-tall aluminum-lithium rocket fuel tank outfitted with sensors (all in the name of science, of course). The idea is to test out how modern composite materials buckle under incredible pressure, in the hope of finding out where the weaknesses might be.
  • Real-life forensic science is rarely as easy or glamorous as its TV counterpart. Actual blood spatter experts, for example, don’t operate with quite the ease of the title character in “Dexter.” But a new study proposes a way to use simple trigonometry to calculate not only the point of origin for blood but also the height above the ground, which previously couldn’t be determined.
  • You knew this day would come: The United States has approved the first deepwater offshore drilling permit given out since the Deepwater Horizon disaster.
  • As strong as metal and as moldable as plastic: Yale scientist Jan Schroers’ new super-alloys.
  • Half of adult males may be carrying the human papillomavirus (HPV), according to a study in The Lancet. It often lingers quietly but is transmitted sexually and is the cause of most cervical cancers in women.
  • Strictly speaking, there should be no blue whales.” So begins DISCOVER blogger Carl Zimmer as he explores the curious question of why blue whales, with so many more cells than human beings and so many chances for those cells to go wrong, are not killed by cancer at an astounding rate.

Image: NASA

Study: How Suspects' DNA Traces Can Reveal Their Hair Color

By Andrew Moseman | January 4, 2011 4:06 pm

However far-fetched some of their science has been, the barrage of forensic science TV shows during the last decade has ingrained into people the idea that even the most cautious criminals (we’re looking at you here, Dexter) leave something of themselves behind at the scene of the crime. And thanks to the march of genetic science and sequencing, those bits of someone can tell more and more about them. Even their hair.

In a study coming soon to the journal Human Genetics, Manfred Kayser and colleagues identify genetic markers that can predict a person’s hair color.

The researchers studied DNA and hair colour information from hundreds of Europeans. They investigated genes previously known to influence the differences in hair colour. “We identified 13 ‘DNA markers’ from 11 genes that are informative to predict a person’s hair colour,” said Professor Kayser. [BBC News]

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Scientists Identify Mummified Head of a Murdered French King

By Andrew Moseman | December 16, 2010 10:35 am

HenriIVIt’s a hard life (and death) being a French king. Even if you’re popular, you’re assassinated. Revolutionaries disinter your body long after your death and make off with your mummified head. And then finally, 400 years after your death, your head supposedly turns up in the garage of a collector.

This week a team led by Philippe Charlier reports to have identified the head of the monarch in this story, France’s King Henri IV. The researchers report their find in the Christmas issue of the British Medical Journal, which is known for its tradition of bizarre topics and occasional spoof articles, but Charlier and company appear to be on the level about identifying the remains of the first Bourbon king.

Known as “the green gallant” in his time, Henri’s extraordinary popularity didn’t prevent him from being whacked in 1610—then having his remains ransacked by revolutionaries nearly 200 years later. Reports of his head passing between private hands have surfaced over the centuries, most recently after one collector bought it for three francs in 1919, then tried—and failed—to have it authenticated for display in French museums. It came into possession of an 84 year-old man who has kept it stashed in his garage since 1955. [TIME]

Charlier and colleagues say they could not recover uncontaminated samples of mitochondrial DNA, which would have allowed for genetic testing. So, as an alternative, they found several ways to compare what was left of the embalmed head to what historians know about Henri IV (not to be confused with Henry IV of England, subject of two Shakespeare plays).

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CATEGORIZED UNDER: Health & Medicine

Forensic Scientists Can Tell Your Age from a Drop of Blood

By Eliza Strickland | November 23, 2010 2:45 pm

crime-sceneForensic scientists of the future may soon have a new tool at their disposal. Given a drop of blood, researchers in the Netherlands have roughly determined the age of the person it came from. But for now, it really is rough–the researchers found they could only estimate a person’s age to within 9 years.

Currently, a crime scene investigator who obtained a spot of blood can check its DNA to see if it matches a known suspect or someone in a law enforcement database, and can use the DNA to determine a few other characteristics like gender and eye color. But age is tougher to estimate. Lead researcher Manfred Kayser, who works on forensic molecular biology at Erasmus University Medical Centre, explains that the best methods of determining age rely on testing bones or teeth, but he wanted to find a method that didn’t require skeletal remains.

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CATEGORIZED UNDER: Health & Medicine, Technology

A Nuclear Bomb’s Debris Could Reveal How It Was Made

By Andrew Moseman | November 9, 2010 10:45 am

TrinityIf a country fires an airborne nuclear missile, the source of the attack is obvious. But what about the more fluid threat that hangs over the 21st century—terrorists sneaking a nuclear device into a city and setting it off? In a study in the Proceedings of the National Academy of Sciences this week, researchers suggest that even in the charred aftermath of a nuclear explosion, there could be evidence left behind that helps to identify the source of the bomb.

Physicist Albert Fahey and company went back to the beginning of the atomic age, to the United States’ first atomic bomb test in New Mexico in July 1945. As that bomb test was called “Trinity,” the glass left behind by the blast is called “trinitite.” Fahey obtained some of that glass to show that all these years later, it still contained evidence of the bomb’s makeup.

“Prior to this study, people didn’t realise that other components of the bomb could be discerned from looking at ground debris and seeing what’s associated [with it],” said Dr Fahey. “But there are some distinctive signatures that were in the bomb other than fission products and plutonium, and that gives you hope that you can get some additional information out of it – like where it was made.” [BBC News]

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CATEGORIZED UNDER: Physics & Math, Technology

Police Nabbed Serial Killer Suspect by Stumbling on His Son's DNA

By Andrew Moseman | July 9, 2010 3:46 pm

DNALos Angeles police say that Lonnie Franklin Jr. may be the “grim sleeper” serial killer they have sought for more than 20 years. And if indeed they do have their man, they have his son to thank—for getting arrested himself.

Franklin is one of the first major suspects nabbed by police using familial DNA. With this controversial method, investigators look for partial matches between DNA left at a crime scene and DNA profiles that are stored in police databases; a partial match may indicate that the person is related to the target individual sought by the cops.

The trail began to heat up when the DNA of Franklin’s son was entered in a state database after he was convicted in a weapons case, authorities said. The son’s DNA was similar to genetic material found on the victims, and authorities soon began following around Franklin to get his DNA and see if he was the suspected killer [AP].

The cops posed as waiters at a restaurant where the elder Franklin ate, which is how they obtained a complete DNA sample from him–they grabbed a plate and napkin he tossed after eating a slice of pizza. The investigators say that when they found the match to the samples in their evidence, it eased 25 years of frustration at not being able to track him down.

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CATEGORIZED UNDER: Living World, Technology

How Beer Bears Witness: Your Hair Shows Where You've Been Drinking

By Andrew Moseman | July 1, 2010 11:16 am

beveragefingerprintI know, I know—after the flawless execution of the perfect crime, all you want to do is put your feet up at a bar with a patio and savor a cold one. However, a new study out in the Journal of Agricultural and Food Chemistry says that the bottle of Budweiser is just filling your body with incriminating evidence.

It’s no secret that traces of what you consume can end up in your hair (hence hair-based drug tests). The researchers wanted to know if they could find a signature in those traces that would show not just what you’ve been using, but also where it came from. So they traveled to a bunch of different U.S. cities and tested out a few of America’s favorite beverage products—Budweiser, Coke, and bottled water—to see if their chemical fingerprints matched up with the fingerprint of the local water supply.

Researchers found that water samples from 33 cities across the United States could be reliably traced back to their origin based on their isotope ratios. And because the human body breaks down water’s constituent atoms of hydrogen and oxygen to construct the proteins that make hair cells, those cells can preserve the record of a person’s travels [ScienceNOW].

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CATEGORIZED UNDER: Environment, Technology

Could Forensic Scientists ID You Based on Your “Bacterial Fingerprint”?

By Smriti Rao | March 16, 2010 11:28 am

keyboardIf you thought that fingerprints or DNA fragments were the only bits of forensic evidence that could pin you to a scene of a crime, then think again. Researchers at the University of Colorado, Boulder have found preliminary evidence suggesting that you can be identified from the unique mix of bacteria that lives on you.

Each person, they say, is a teeming petri dish of bacteria, but the composition varies from person to person. Every place a person goes and each thing he touches is smudged with his unique “microbial fingerprint.” The bacterial mixes are so specific to individuals that researchers found that they could pair up individual computer keyboards with their owners–just by matching the bacteria found on the keyboard to the bacteria found on the person’s fingertips. Describing their findings in the journal Proceedings of the National Academy of Sciences, scientists write that that if this bacterial fingerprint technique is refined, it could one day help in forensic investigations.

The Human Microbiome Project has already found that different body parts harbor different kinds of microbes. Study coauthors Noah Fierer and Rob Knight note that these colonies don’t change much over time. No amount of hand-washing will change a person’s microbial make-up, they say.

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CATEGORIZED UNDER: Health & Medicine, Technology

Investigation Says Texas Gave Newborns' DNA to Military Database

By Andrew Moseman | February 25, 2010 2:53 pm

Cute Baby Boy Isolated on WhiteFrom 2002 until a lawsuit last year, the state of Texas took the small blood samples taken from newborns to screen for diseases, and saved them without the parents’ consent. Texas always said it did this for research purposes, of which there are many. But there was a wee detail about all this that didn’t come to light until an investigation published this week in the Texas Tribune. According to the Tribune, between 2003 and 2007, Texas quietly handed over 800 of those samples to the military for a project to create a database of mitochondrial DNA, which people inherit from their mother.

Like virtually every state, Texas routinely screens almost all newborns for rare diseases, collecting a few drops of blood at birth. In recent years many states, Texas included, have stored the samples and offered them up for research, mainly in pediatrics [ScienceInsider]. Because the samples are anonymous, researchers decided it was okay to use them without parental consent. However, the Tribune’s investigation uncovered emails showing Texas state officials publicized the use of DNA taken from newborns in studies on childhood disease, but deliberately dissuaded state employees from divulging the use of baby blood in establishing a DNA database [Popular Science].

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CATEGORIZED UNDER: Health & Medicine, Technology

Verdict on Forensic Science: It's Quite Bad

By Rachel Cernansky | February 20, 2009 2:16 pm

forensic.jpgForensic science, often used to produce evidence for criminal trials using such techniques as fingerprint analysis, is “badly fragmented” and unreliable in the U.S., according to a report by the National Academy of Sciences. Crime laboratories around the country are grossly underfunded, lack a scientific foundation and are compromised by critical delays in analyzing physical evidence…. The report calls into question the scientific merit of virtually every commonly used forensic method, including analysis of fingerprints, hair, fibers, blood spatters, [and] ballistics [The New York Times].

According to the report “no forensic method”—with the notable exception of DNA analysis—”has been rigorously shown able to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source.” Of particular concern is the use of comparative forensic methods like hair or fingerprint analysis to match a piece of evidence to a particular person, weapon, or place [New Scientist].

DNA was excluded from the criticism because “the chances of a false positive are minuscule, but also because the likelihood of such errors is quantifiable. Studies have been conducted on the amount of genetic variation among individuals, so an examiner can state in numerical terms the chances that a declared match is wrong.” Other forensic techniques, however, have not been studied to determine how many sources might share similar features, or to quantify the level of uncertainty in any measurement made.

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