Entries Tagged "law enforcement"

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The Unreliability of Eyewitness Testimony

Interesting article:

The reliability of witness testimony is a vastly complex subject, but legal scholars and forensic psychologists say it’s possible to extract the truth from contradictory accounts and evolving memories. According to Barbara Tversky, professor emerita of psychology at Stanford University, the bottom line is this: “All other things equal, earlier recountings are more likely to be accurate than later ones. The longer the delay, the more likely that subsequent information will get confused with the target memory.”

[…]

Memory is a reconstructive process, says Richard Wise, a forensic psychologist at the University of North Dakota. “When an eyewitness recalls a crime, he or she must reconstruct his or her memory of the crime.” This, he says, is an unconscious process. To reconstruct a memory, the eyewitness draws upon several sources of information, only one being his or her actual recollection.

“To fill in gaps in memory, the eyewitness relies upon his or her expectation, attitudes, prejudices, bias, and prior knowledge. Furthermore, information supplied to an eyewitness after a crime (i.e., post-event information) by the police, prosecutor, other eyewitnesses, media, etc., can alter an eyewitness’s memory of the crime,” Wise said in an email.

That external input is what makes eyewitness testimony so unreliable. Eyewitnesses are generally unaware that their memory has been altered by post-event information, and feel convinced they’re recalling only the incident itself. “Once an eyewitness’s memory of the crime has been altered by post-event information, it is difficult or impossible to restore the eyewitness’s original memory of the crime,” Wise told Life’s Little Mysteries.

Posted on June 4, 2012 at 6:36 AM • View Comments

The Banality of Surveillance Photos

Interesting essay on a trove on surveillance photos from Cold War-era Prague.

Cops, even secret cops, are for the most part ordinary people. Working stiffs concerned with holding down jobs and earning a living. Even those who thought it was important to find enemies recognized the absurdity of their task.

I take photos all the time and these empty blurry frames tell me that they were made intentionally. Shot out of boredom, as little acts of defiance, the secret police wandered the streets of Prague for twenty years taking lousy pictures of people from far away because a job is a job.

Occasionally something interesting happened, like spotting a hot stylish, American made Ford Mustang Sally. However, it must have been an awful job, with dull days that turned into months and years, of killing time between lunch and dinner.

Posted on May 24, 2012 at 6:17 AM • View Comments

Biometric Passports Make it Harder for Undercover CIA Officers

Last year, I wrote about how social media sites are making it harder than ever for undercover police officers. This story talks about how biometric passports are making it harder than ever for undercover CIA agents.

Busy spy crossroads such as Dubai, Jordan, India and many E.U. points of entry are employing iris scanners to link eyeballs irrevocably to a particular name. Likewise, the increasing use of biometric passports, which are embedded with microchips containing a person’s face, sex, fingerprints, date and place of birth, and other personal data, are increasingly replacing the old paper ones. For a clandestine field operative, flying under a false name could be a one-way ticket to a headquarters desk, since they’re irrevocably chained to whatever name and passport they used.

“If you go to one of those countries under an alias, you can’t go again under another name,” explains a career spook, who spoke on condition of anonymity because he remains an agency consultant. “So it’s a one-time thing—one and done. The biometric data on your passport, and maybe your iris, too, has been linked forever to whatever name was on your passport the first time. You can’t show up again under a different name with the same data.”

Posted on April 26, 2012 at 6:57 AM • View Comments

Bomb Threats As a Denial-of-Service Attack

The University of Pittsburgh has been the recipient of 50 bomb threats in the past two months (over 30 during the last week). Each time, the university evacuates the threatened building, searches it top to bottom—one of the threatened buildings is the 42-story Cathedral of Learning—finds nothing, and eventually resumes classes. This seems to be nothing more than a very effective denial-of-service attack.

Police have no leads. The threats started out as handwritten messages on bathroom walls, but are now being sent via e-mail and anonymous remailers. (Here is a blog and a
Google Docs spreadsheet documenting the individual threats.)

The University is implementing some pretty annoying security theater in response:

To enter secured buildings, we all will need to present a University of Pittsburgh ID card. It is important to understand that book bags, backpacks and packages will not be allowed. There will be single entrances to buildings so there will be longer waiting times to get into the buildings. In addition, non-University of Pittsburgh residents will not be allowed in the residence halls.

I can’t see how this will help, but what else can the University do? Their incentives are such that they’re stuck overreacting. If they ignore the threats and they’re wrong, people will be fired. If they overreact to the threats and they’re wrong, they’ll be forgiven. There’s no incentive to do an actual cost-benefit analysis of the security measures.

For the attacker, though, the cost-benefit payoff is enormous. E-mails are cheap, and the response they induce is very expensive.

If you have any information about the bomb threatener, contact the FBI. There’s a $50,000 reward waiting for you. For the university, paying that would be a bargain.

Posted on April 12, 2012 at 1:34 PM • View Comments

Law Enforcement Forensics Tools Against Smart Phones

Turns out the password can be easily bypassed:

XRY works by first jailbreaking the handset. According to Micro Systemation, no ‘backdoors’ created by Apple used, but instead it makes use of security flaws in the operating system the same way that regular jailbreakers do.

Once the iPhone has been jailbroken, the tool then goes on to ‘brute-force’ the passcode, trying every possible four digit combination until the correct password has been found. Given the limited number of possible combinations for a four-digit passcode—10,000, ranging from 0000 to 9999—this doesn’t take long.

Once the handset has been jailbroken and the passcode guessed, all the data on the handset, including call logs, messages, contacts, GPS data and even keystrokes, can be accessed and examined.

One of the morals is to use an eight-digit passcode.

EDITED TO ADD (4/13): This has been debunked. The 1Password blog has a fairly lengthy post discussing the details of the XRY tool.

Posted on April 3, 2012 at 2:01 PM • View Comments

Biases in Forensic Science

Some errors in forensic science may be the result of the biases of the examiners:

Though they cannot prove it, Dr Dror and Dr Hampikian suspect the difference in contextual information given to the examiners was the cause of the different results. The original pair may have subliminally interpreted ambiguous information in a way helpful to the prosecution, even though they did not consciously realise what they were doing.

[…]

This one example does not prove the existence of a systematic problem. But it does point to a sloppy approach to science. According to Norah Rudin, a forensic-DNA consultant in Mountain View, California, forensic scientists are beginning to accept that cognitive bias exists, but there is still a lot of resistance to the idea, because examiners take the criticism personally and feel they are being accused of doing bad science. According to Dr Rudin, the attitude that cognitive bias can somehow be willed away, by education, training or good intentions, is still pervasive.

Posted on January 31, 2012 at 11:13 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.