NPR logo

Voice 'Fingerprints' Change Crime-Solving

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript
Voice 'Fingerprints' Change Crime-Solving


Voice 'Fingerprints' Change Crime-Solving

Voice 'Fingerprints' Change Crime-Solving

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Second of a three-part series.

Is this the real Osama bin Laden? When a new bin Laden videotape shows up, FBI investigators use voice technology to verify its authenticity. Here, a still image taken from a videotape that aired on Al-Jazeera on Sept. 10, 2003. Getty Images hide caption

toggle caption
Getty Images

The FBI is trying to develop a system that could make your voice as unique and recognizable as your fingerprint. Although not yet at its peak potential, the technology currently helps investigators with tasks such as verifying Osama bin Laden videos and locating gunshots.

Running an audio clip of someone's voice through the system, called FASR, prompts bright squiggly lines to rise and fall. Each voice is quite distinct. While the pattern isn't as definitive as DNA, the FBI says, FASR gets pretty close.

When a new Osama bin Laden audio or video tape pops up on the Internet, the forensic analysts at the FBI Audio Lab in Quantico, Va., process the voice through this system. The results allow them report whether the tape is authentic.

It doesn't matter what language is being spoken, Steven Lanser who heads up the FBI audio team says. Regardless of whether one is speaking Arabic, Urdu or English, a voice follows a particular pattern.

"We use an automated system and that system looks at a variety of different voice features that it extracts automatically," Lanser says. "Then it gives us a confidence score of the speaker versus an unknown speaker."

In other words, does this Osama bin Laden sound like that Osama bin Laden?

Lanser says the FASR system science is not perfect. By itself, a match on FASR isn't enough to convict anyone in a court of law. Added to other pieces of evidence, however, it could provide intelligence to either include or eliminate a suspect.

Gunshot Detection

The new world of audio forensics helps with more traditional crime-fighting as well. Gunshot-detection systems are the next frontier in audio forensics, some law enforcement officials say. Cities across the country are starting to put noise sensors on rooftops. The system analyzes the time it takes for the sound of gunfire to travel to various sensors and creates a picture of where the gun went off using GPS, providing key information to police within seconds.

Minneapolis Police Chief Tim Dolan has used the technology, called ShotSpotter, in two high-crime areas for several years. In a recent case, Dolan says, a 16-year-old girl was caught in gang-related crossfire with police. The suspects claimed the officers fired first.

"We were able to tell from the ShotSpotter exactly how many shots were fired and were able to break down who shot when," he says. "It made a big difference and was able to take away an alibi from the people involved in that shooting.

The technology provides a street address for where shots were fired. And if there is more than one shot, it can determine which direction the person firing the shots was going.

While Dolan says the system has been helpful in Minnesota, the technology isn't perfect. Ice popping or the crack of roofing guns could set off the sensors. Consequently, in the beginning there were many false alarms. A lot of those problems went away when Minneapolis started coordinating its gun-detection systems with cameras, Dolan says.

"We're getting fewer false positives and it is getting better," he says. "What's out here today is much better than what was out there three years ago."

Other local law enforcement agencies appear to agree: More than 20 American cities have installed new gunshot-detection systems.

FBI's New Technology Revolutionizes DNA Analysis

FBI's New Technology Revolutionizes DNA Analysis

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

First of a three-part series.

The FBI is using robotic processes to help analyze DNA at its crime laboratory at Quantico, Va. FBI hide caption

toggle caption

The FBI is using robotic processes to help analyze DNA at its crime laboratory at Quantico, Va.


More in the Series

In Depth

More than 200 wrongly convicted people have been exonerated based on DNA evidence, which has also brought convictions in decades-old cases. As law enforcement finds new ways to use DNA, those new techniques raise new ethical questions.

Criminals' genetic code is part of a national database compiled by the FBI. FBI hide caption

toggle caption

Criminals' genetic code is part of a national database compiled by the FBI.


Blood splatter patterns... DNA typing... Crime scene reconstruction... They have all became dinner table conversation after the O.J. Simpson trial and television shows like CSI. In the first of a series about high-tech forensics, we visit the FBI Crime Lab in Quantico, Va., where experts are finding new and better uses for what many people see as a forensic sure thing — DNA.

The 1995 double-murder trial of O.J. Simpson fundamentally changed the way Americans saw criminal evidence. Forensic details suddenly became dinner table conversation. Television programs like CSI have only added to the allure of forensics.

Everyone has become an armchair crime-scene specialist, and that has meant the bar has been raised. In a courtroom, jurors are expecting to see something like what they see on television: forensic proof that they think any good investigator — like the ones on TV — should be able to find.

"The data is suggesting that interviews of jurors have them saying they would convict, if only the investigators had done DNA," said Mitchell Holland, a professor of Forensic Science at Penn State. "Some jurors are saying they needed this forensic evidence when there was probably enough in the case already to convict."

Solving the Unsolvable

It isn't just a hot television series that is creating the problem. Expectations are rising because, frankly, the science is getting better. Not so long ago, forensic experts needed a sample about the size of a nickel for processing. Now it just needs to be the size of a pin prick to do the trick.

That means that cases unsolvable just a decade ago are now ripe for reopening.

The FBI's nuclear DNA lab at Quantico, Va., hums with activity, though much of that movement is robotic. A new machine there allows a robot to process DNA samples at an exponentially higher rate than humans ever could. This is where the FBI is processing punch cards with DNA samples from the nation's federal offenders.

The FBI is trying to get a roster of prior criminals into a national database that will not only help law enforcement solve new crimes, but potentially old ones, too.

Look inside the new processing machine and you see a robotic arm skimming along a long tray of test tubes. Each contains a small blood sample which is bathed in a sort of chemical detergent that breaks the human cells open. DNA is then released inside the test tube and settles to the bottom — like sediment in a bottle of wine.

That sediment is fed into another instrument that reads its genetic code to include in a database. Just a handful of years ago, compiling that kind of database would have taken human technicians years. The robot can do 500 samples a day — many more than a human ever could.

Robot in the Lab

Jennifer Luttman runs the Convicted Offender program at the FBI Lab. She says that the FBI still uses people to find the DNA at a crime scene, but steps that come after that are easily automated.

"We still use humans to look for the stains, to test for blood, to test for semen, to cut out the stains," she said. "Only a human can do that because they need to see how much is there and that's all based on experience."

But Luttman says that once the DNA is extracted and purified, robots can take care of the rote processes.

Down the hall from the nuclear DNA lab, other FBI scientists are trying to tug clues from a different kind of DNA, called mitochondrial DNA.

If you think of regular DNA as being part of the yolk of an egg, mitochondrial DNA is in the white. Regular DNA is passed on from both parents. Mitochondrial DNA comes just from the mother. So mitochondrial DNA isn't as useful for identification as nuclear DNA. But it doesn't break down as quickly — and that makes it vitally important to "cold" cases.

Alice Eisenberg, head of the FBI's Mitochondrial DNA Analysis lab, says cold cases are the meat and potatoes of her unit's operation. Typically, her technicians are dealing with bone and hair samples that have been sitting on evidence room shelves for years.

"No one was able to perform DNA analysis on them until we came along with our mitochondrial DNA technology," she said.

Weighing Molecules

The newest wrinkle involves a rather innocuous-looking machine called a mass spectrometer, which is, in essence, a glorified scale that weighs individual molecules. The actual machine is not very big. It is about the length of a kitchen counter and a little over 5 feet tall. Inside, little robotic arms move trays around a series of short towers.

Up to now, law enforcement has mostly used it to identify chemicals, like accelerants around suspicious fires. The FBI lab is the first to use it to measure mitochondrial DNA in crime work.

The idea, in a very simplified way, is to separate out the DNA's component parts by weight.

That becomes important in an event like the World Trade Center attack, in which remains end up co-mingled, making it hard to tell which DNA is which. The mass spectrometer is able to use weights to identify different fragments of the DNA.

Les McCurdy, a forensic examiner in the DNA analysis lab, likened the instrument's work on DNA to a scale weighing a pocketful of coins.

"You have pennies, nickels, dimes and quarters. Each of those coins has a different weight," he said, adding that if he had a pocketful of coins and put it on a scale, he could tell the difference between each coin. "It is the same type of thing we are doing with mitochondrial DNA with this instrument."

Separating DNA

Essentially the machine helps analysts shake out and identify several individuals from a DNA mixture. The robot picks up a plate, reads a bar code on its side and cleans the DNA. Then, using magnetic beads, the robot separates the DNA so it can put it in the mass spectrometer for weighing. A computer then records the various weights and DNA combinations.

McCurdy said it was one of the most exciting projects he's worked on at the FBI.

"It will have tremendous application," he said. "I think it is really going to open up all new kinds of evidence and all new kinds of cases. It will have a huge impact on how we can assist different investigations."

This new mass spectrometer technology is still in its infancy, but it is part of a larger program to expand the uses of DNA. And even people outside the FBI, like Penn State's Holland, see new uses for DNA.

"The power of DNA is just beginning to emerge," he said. "That's really exciting."

The question is whether these new DNA advances will raise the forensics bar even higher — with jurors coming to expect science to wring doubt out of their deliberations during a trial. The FBI is quick to say that new DNA science doesn't just assign guilt. Almost one-third of their DNA work goes toward exonerating suspects. Because of that, they say, these DNA advances are good for everyone.