Recently in Forensic Evidence Category

January 25, 2010

Lab Analysts in the Courtroom- Confrontation Over the Confrontation Clause Continues

In the 2009 Melendez-Diaz case (decided by a 5-4 majority vote), the U.S. Supreme Court decided that the Sixth Amendment's Confrontation Clause gives criminal defendants the right to cross examine lab analysts who run tests that determine such matters as the alcohol content of a driver's blood or whether white powder is an illegal drug. Outraged prosecutors in many states have attacked the practical effect of the decision.  They argue that under-funded and under-staffed forensic labs were unable to keep up with the demands for testing even before Melendez-Diaz was decided, and that if analysts have to hang around courtrooms the labs will fall so far behind that cases will have to be dismissed.  Prosecutors also argue that cross examination is unnecessary when analysts don't exercise subjective judgment but instead simply report the results of tests that machines carry out.  

In Briscoe v. Virgina (2010) the Court passed up a chance to clarify the scope of Melendez-DiazBriscoe involved the legitimacy of a state law that allowed prosecutors to offer lab test reports into evidence without calling the analysts as witnesses, and then (upon request from the defendant) producing the analysts for defendants to examine as part of the defense case.  The Court chose not to decide whether this procedure is constitutional, instead returning the case to the state for "consideration in the light of the decision in Melendez-Diaz."  So for some time to come, the increasingly bitter confrontation over the scope of the Confrontation Clause continues.

November 4, 2009

Police dog lineups- round up the usual scents

Police officers commonly bring trained sniffer dogs to crime scenes to pick up scents and track suspecta to nearby hiding spots.  Dog scent lineups take this approach a large step further.  Dog scent lineups occur when police officers give a dog crime-scene related objects to smell.  The officers then present the dog with containers swabbed with sample objects taken from different people.  If the dog reacts to the scent in one of the containers, does that mean that the person from whom an object was taken was at the crime scene?

Curvis Bickham's sad story suggests that the answer might be "No."  Poor Bickham sat in jail for 8 months after the results of a dog scent lineup conducted by Texas Deputy Sheriff Keith Picket led the police to arrest Bickham for killing 3 people.  When someone else finally confessed to the murders, the police realized that the dog had barked up the wrong tree and released Bickham from jail.

Curvis is not the only victim of Picket's charge.  Another of Picket's dog scent lineups led the police to arrest Ronald Curtis for committing a string of burglaries.  Curtis sat in jail for 9 months, until the police realized that store videos of the burglaries proved that Curtis looked nothing like the burglar.

Injustices like these probably won't stop Picket and others from conducting dog scent lineups.  We continue to search for reliable forensic methods of proof, and at least police dogs don't have motives to lie.  But until we can be more confident that dogs are properly trained and standards for conducting dog scent lineups properly emerge, dog scent lineups emit a foul odor.

November 2, 2009

Text Your Way to Prison

As a California bicycle commuter, I'm angry and scared because I see so many people continuing to use cell phones while driving long after doing so was made a crime.

In England, Phillippa Curtis (age 22) was recently convicted of driving while distracted by using a cell phone and sentenced to 21 months in prison.  Curtis smashed into a stopped car and killed its occupant, Victoria McBride.  An analysis of Curtis' cell phone showed that while she was driving, Curtis had sent and received about 20 text messages in the minutes leading up to the crash.  She'd just received another message seconds before the crash, and may have been about to open it when she killed Ms. McBride. 

Curtis was convicted even though she was not actively texting at the moment of the crash.  The evidence convinced the jury that Curtis was distracted by texting while driving, and that supports the guilty verdict.

What a sad story.  I hope drivers here get the text message.

June 26, 2009

Melendez-Diaz Raises the 6th Amendment's Price Tag

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Melendez-Diaz v. Massachusetts, decided by the U.S. Supreme Court on June 25, 2009, is the latest salvo in the Sixth Amendment Wars.  Since 2004, one of the most divisive issues the Court has faced has concerned the meaning of the 6th Amendment's "Confrontation Clause."  So far, the Scalia-led majority insisted that the prosecution produce live witnesses instead of hearsay, and Scalia carried the day again in Melendez-Diaz.

The case involved the admissibility of certificates prepared by government lab technicians and stating under oath that the powder that police officers had seized was cocaine.  The prosecutor offered the certificates into evidence in lieu of calling the lab technician who had performed the test, and the Court ruled that doing so violated the 6th Amendment and invalidated the conviction.

The decision has the potential to make drug prosecutions too costly to pursue.  Many testing labs are already hard-pressed to keep up with the demands for test results.  If the technicians who carry out the testing also have to sit around courthouses waiting to testify, the backlogs will grow longer. The costs of the decision may be prohibitively high in rural states, where only one or two labs run tests for the entire state.  And when substances are sent to the FBI in Washington, D.C. for testing, Melendez-Diaz requires technicians to travel all over the country to testify regarding test results that they probably can't recall -- other than by looking at their certificate, anyway. 

A spokesperson for a national DIstrict Attorneys organization calls the decision a "train wreck" for prosecutors, and he may be right.  However, Justice Scalia has the mind-set of a junkyard dog when it comes to the protection of his 2004 Crawford decision To paraphrase an old homily, Scalia seems to believe that it is better that 99 defendants go free than one bit of hearsay escapes the 6th Amendment.              

March 12, 2009

Ricardo Rachell: The Crimnal Injustice System in a Nutshell

Ricardo Rachell was released from a Texas prison in December 2008 after serving more than 5 years in prison for the rape of a child that he didn't commit.  Rachell's tragic story provides a snapshot of the common ills that afflict our criminal justice system and that I have discussed in earlier blog entries.

  1. Rachell was convicted largely on the basis of mistaken eyewitness identifications made by the 8-year-old male victim and his friend. More than any other factor, mistaken eyewitness identifications are the leading cause of wrongful convictions. Amazingly, the boys were believed even though Rachell's face is terribly disfigured from a shotgun blast he had suffered years earlier, and the boys initially failed to mention anything unusual about the attacker's face to the police. 
  2. DNA testing of physical evidence proved that Rachell did not commit the crime.  However, even though the evidence was available for testing shortly after the crime took place in 2002, it wasn't tested until 2008. The prosecutor claims that the defense trial lawyer should have requested DNA testing; the defense lawyer claims that he didn't know that physical evidence was available for testing; and the incompetent DNA lab was closed down around the time Rachell was convicted anyway.
  3. Pat Lykos, the current District Attorney of Harris County, Texas (where Rachell was convicted) blames the prosecutors, the defense lawyers, the police, and the crime lab for the wrongful conviction.  But even if Lykos had 10 hands, she probably wouldn't have enough fingers to point at the causes of this injustice.
February 18, 2009

Update: Crime Labs Remain Under the Microscope

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After a lengthy study, the National Academy of Sciences has called for a thorough overhaul of the nation's crime labs. (To read the Academy's news release, visit their website.)

The report described a sort of "sliding scale" of forensic reliability. The most reliable types of lab tests are "objective" and are based on biological or chemical analysis. DNA analysis is at the top of the scale; its results are consistently reliable. (Unfortunately, what the report does not say is that many DNA labs are so backlogged that statutes of limitations often expire before testing can be carried out.)

Reliability problems crop up when crime lab analysis rests on "subjective" factors.  Fingerprint, bitemark, toolmark, and similar experts perform their work through subjective interpretation of their samples -- largely in the absence of national standards and protocols.  In many cases, the basic principles and techniques underlying a field of forensic expertise have never been formally studied or established.  Moreover, the labs that carry out the tests often work for police and prosecutors (raising issues of impartiality), and their operations are often haphazard with uncertain quality control.

The report may impel judges to take their "gate-keeping" role more seriously. Instead of allowing forensic experts to testify because "we've always allowed these kinds of experts to testify," judges may require prosecutors to demonstrate that a field of expertise has been subjected to analysis and has been shown to be reliable.

Apart from what happens in court, the report may also encourage all levels of government to invest in our nation's crime labs.  As matters stand now, it's hard to be confident that forensic test results are reliably identifying the guilty and freeing the innocent.

February 5, 2009

Crime Labs Under the Microscope

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Forensic specialists in crime labs match fingerprints, perform DNA analysis, link bullets to weapons, and perform other essential functions of scientific police work. Their accuracy and efficiency is vital to the effectiveness of our criminal justice system. If they screw up, innocent people are convicted and guilty people go free.

Sometime this month, the National Academy of Sciences will release a report blasting the quality of forensic testing in U.S. crime labs. Technicians, many among them employed by police departments, are often poorly-trained and exaggerate the accuracy of tests when defending their results in court. Moreover, the lack of standards for training technicians and carrying out forensic tests means that labs can differ greatly in quality. It's not a pretty picture, and clearly it conflicts with the glorious images of forensic scientists as shown in popular TV shows.

The forthcoming report's attack on the quality of crime labs is the Academy's broadest call yet for reform. A few years ago, a previous report knocked the pins out from under a testing technique known as "bullet lead test analysis". The FBI at one time claimed that each box of bullets had a unique chemical "signature" and that it could use these signatures to determine whether a particular bullet came from a particular box of bullets. Hundreds of people were convicted partly on the basis of such forensic evidence before the Academy demonstrated that the testing method was invalid.

Any reforms that the latest report calls for will undoubtedly be costly to implement and will not be accomplished overnight. As for the present, you can bet that the report will stimulate criminal defense attorneys to more vigorously attack the accuracy of forensic test results with this new ammunition.

December 18, 2008

Bitemark Evidence Needs Orthodontia

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Bitemark evidence is a tool that prosecutors sometimes use to connect defendants to crimes. The testimony of a bitemark expert (who carries the fancy, jury-impressing title of "forensic odontologist") usually goes something like this: "I compared the teethmarks found on the victim's right arm with the defendant's dental prints.  In my opinion, a match exists; the defendant was responsible for the teethmarks." 

Though judges routinely admit bitemark testimony, recent studies have undermined its reliability.  Unlike the generally-accepted principle that fingerprints are unique, the uniqueness of dental patterns has never been established. Moreover, bitemark experts usually have to base their conclusions on fragmentary patterns -- say, the marks left by a few teeth. Finally, the proficiency of bitemark experts is uncertain because they have never been scientifically studied.  Thus, it's no surprise that a number of defendants who have been cleared by DNA analysis after they have begun serving their sentences were convicted partly on the basis of mistaken bitemark evidence.

In the future, criminal defense attorneys will no doubt more aggressively challenge the admissibility of bitemark evidence. As "gatekeepers," judges have to remember that prosecutors who want to rely on bitemark evidence have the burden of establishing the reliability of its underlying principles.  If they cannot do so, judges should disregard the fancy trappings of forensic odontologists (advanced degrees, publications, professional associations, good molars) and tell them to bite the dust.

December 10, 2008

The U.S. Supreme Court Considers Whether the Constitution Requires Forensic Lab Experts to Testify at Trial

In the 2004 "Crawford case", the U.S. Supreme Court interpreted the Sixth Amendment's Confrontation Clause to require prosecutors to present live witnesses rather than hearsay whenever the hearsay was "testimonial." The decision has given rise to lots of commentary and court opinions (many of them conflicting) about whether particular types of hearsay are testimonial.  For example, if a domestic violence victim makes an emergency call to a 911 operator, the victim's statements are likely not to be testimonial, meaning that prosecutors can, if necessary, offer a transcript of the call into evidence if the victim refuses to come to court and testify.  On the other hand, if the domestic violence victim talks to a police officer once the emergency is over, the victim's statements are testimonial. If the victim refuses to testify, the prosecutor cannot call the police officer as a witness to testify to what the victim said.

One of the elephants in the Confrontation Clause room is whether lab reports are testimonial.  Every day, hundreds of doctors and other technicians conduct autopsies, test substances to determine whether they are illegal drugs, determine the alcohol context of blood or urine, etc.  They prepare reports of their findings and before Crawford most courts routinely admitted these reports into evidence at trial under long-established hearsay exceptions for business or official records. But if these reports are testimonial, defendants would have the right to insist that the report preparers testify in person.  The ramifications of such a result are potentially huge. If forensic experts have to testify, at the very least trials become longer and lab backlogs will continue to grow because experts who are testifying (or, more likely, waiting to testify) are not conducting tests.

Sometime in early 2009, the U.S. Supreme Court will likely issue an opinion addressing these issues.  The case is Melendez-Diaz v. Massachusetts, and the Court heard arguments in the case in November 2008.  Forensic lab reports certainly look testimonial in that they are prepared by government officials who usually are aware that they may be offered into evidence at trial.  Prosecutors counter that lab reports are not testimonial because they are objective, especially since many of them are simply machine-generated.  Prosecutors also argue that if defendants really want report preparers to testify, the defendants can call them as their own witnesses.

The outcome of Melendez-Diaz is likely to have a huge impact on the day-to-day functioning of the criminal courts.  My prediction: Since the Supremes have been Confrontation Clause-happy, they will rule that most lab reports are testimonial.  

November 9, 2008

DNA and NIJ Go After Burglars

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If only from watching TV shows like "C.S.I.," most of us know that police agencies often rely on DNA analysis to identify the perpetrators of a crime. Of course, TV programs typically focus on bloody, violent crimes; how many viewers would tune in to watch police officers track down jaywalkers?

TV images notwithstanding, in everyday life property crimes such as burglary are far more prevalent than violent ones. The good news, according to a report funded and recently released by the National Institute of Justice (NIJ), is that DNA analysis can also be an effective tool for solving  property crimes.

The NIJ study focused on 5 different police agencies and compared the results of burglary investigations that used only traditional police practices like fingerprint comparisons with the results of investigations in which the agencies also collected and analyzed DNA evidence. DNA emerged as the big winner. For example, when police agencies relied only on traditional methods of investigation, they identified the perpetrators in only 12% of the cases. When they also used DNA analysis, the agencies were able to identify perpetrators in 31% of the cases.

Part of the study's good news was that police officers were just as good at collecting evidence suitable for DNA analysis as forensic technicians. This means that police agencies thinking about expanding the use of DNA analysis to burglary may not have to spend as much money on white lab jackets as they feared.

Nevertheless, the obstacles to using DNA evidence to solve property crimes are considerable. Existing forensic laboratories aren't sufficiently funded to meet the demands for DNA analysis that have already been placed on them. For example, the LAPD has acknowledged that it has a massive backlog of unexamined DNA evidence from violent crimes and that it was uncertain of its ability to find the funding needed to reduce the backlog. And DNA analysis isn't cheap. According to the NIJ report, the average cost of using DNA analysis to arrest burglars who would not have been arrested through the use of traditional police methods was $14,169 per case.

Unless governments are willing to make huge increases in police agency budgets, any use of DNA analysis to solve property crimes will mean a reduction in the use of DNA analysis to solve violent crimes. Thus, while the report's findings were impressive, there's little likelihood that DNA analysis will become a major tool for solving property crimes anytime soon.