Showing posts with label Forensic science. Show all posts
Showing posts with label Forensic science. Show all posts

Tuesday, March 9, 2010

Advances In Science Help Find The Missing

By Tad DiBiase


There are two clear trends I've seen in no body murder/missing persons cases over the past few years.  First is the shortened length of time between when a person goes missing and an arrest for that person's murder. 


The second is advances in forensic science that make no body cases easier to prosecute.  As a result, the past ten years have seen a huge increase in the number of no body murder cases where there are arrests and prosecutions.  Advances in technology are behind both trends.


 Years ago, if you told people your wife or girlfriend ran off with another man or ran off to Europe, it was difficult to verify this.  In the days before cell phones, credit cards and other electronic trails that we all leave behind nowadays, it was virtually impossible to disprove what a murderer might say about his victim. 


However, today is different.  Upon hearing that someone is missing, police (at least the good ones) immediately start checking cell phone and cell tower (which report the physical location of the cell phone) records.   Computer databases contain a wealth of data that police can access. Credit card records show where purchases were made.  Bank records that show if accounts were accessed.   Social security records that reveal whether the "missing person" got another job, made an unemployment claim, or tried to collect benefits from the government.  Airline records showing passenger manifests.  Virtually every person leaves some form of electronic trail, and most of us leave these trails every day.  


The British have such a sophisticated system of surveillance cameras in public places that it is virtually impossible to go about a normal day and avoid being surveilled (if that's a verb) multiple times a day.  Although the United States is not quite as camera friendly, we're getting there.  Therefore, it is very difficult for someone to just disappear and even harder for a murderer to argue that his victim went somewhere but left no trace.  


Many jurisidictions have seven year rules where a person must be missing for seven years before he or she is declared dead.  These laws are not only anachronistic given the modern communication age but are sometimes used by police as an excuse not to investigate a missing persons case as a homicide.  Luckily, over the past ten years,  the police's ability to more quickly determine that it's unlikely the victim just disappeared has meant that the police treat cases as homicides more quickly.  (I believe it is also true that changes in attitudes regarding domestic violence have caused police to be more suspicious when the missing victim was in an abusive relationship.)  We now see a lot more cases with arrests within months of the person going missing as opposed to years later.  


Second,  forensic advances over the past 20 years make it much easier to investigate, close and prosecute a no body case.  Because of its prevalence, we sometimes forget that DNA testing is a relatively new technology and its first use in court was less than 25 years ago.  Moreover, DNA advances now permit forensic scientists to test not only microscopically tiny pieces of evidence but old DNA and degraded DNA to an extent not possible even ten years ago.  


These scientific advances have led to the reopening of thousands of cold cases and missing persons cases from years ago.  Previously getting a tiny speck of blood from a crime scene years after the murder was not much help because even if it could somehow be tested, forensic science would only permit a conclusion as to the blood type of the person who spilled the blood.  With there only being four blood types, this information was hardly damning.  


Today, a speck of blood (or other body fluid) many years old can prove a suspect's identity to a reasonable scientific conclusion.  And it's not just DNA advances.  Searching fingerprints is easier and faster than 20 years ago and trace evidence (hair, fiber, etc.) has also advanced.  New sciences come online  every year that hold out the promise of improved crime solving, including controversial scientific techniques such as DNA tests that claim they can type race.  


As I tell families all the time, never give up hope because you never know when the next scientific advance might be the one that solves your case.
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Wednesday, February 10, 2010

Interrogation of Reluctant Witnesses

By Tad DiBiase


I'm not a detective (although my brother is) and I don't play one on TV.  Nonetheless during my career as a prosecutor trying mostly murder cases I not only watched a lot of interviews and interrogations but did quite a few myself.  More than once the detectives on my cases accused me of wanting to be a detective more than wanting to be a prosecutor and to that charge I plead guilty.


Interviews and interrogations are critical to resolving many homicide and violent crime cases.  Often murder cases,  particularly domestic murders and no body murders, either do not have forensic evidence or the forensic evidence is not particularly damning, for example, in a domestic murder, finding the suspect's DNA on the scene may not be very incriminating if the victim and the suspect were in a relationship.  Therefore convincing a reluctant eyewitness to come forward with evidence or testimony or the confession of a suspect may mean the difference between closing a case with an arrest and having a case grow cold. 


My view on interviews of reluctant witnesses and interrogations changed over time.  When I was a junior prosecutor I was all about good cop/bad cop. I was always the bad cop and believed that it was best to confront a liar as such and to pound away on the witness or suspect until he gave it up.  (To be fair, most of the witnesses to DC murders tend not to be school teachers and bus drivers but hardened thugs and drug dealers who were used to being questioned by police and prosecutors.)  


As time went on, however,  I watched more experienced prosecutors and veteran homicide detectives,  I realized that, while playing bad cop was fun, it was often unproductive.  Most witnesses and suspects,  if they did confess,  were more likely to tell the truth if the detective or prosecutor speaking to them established a bond, not hit them over the head with a bat (metaphorically speaking of course).  I thought of this recently as I read of the controversy about the questioning of suspected terror suspects.  Although I  reject the idea that an interrogation of terrorists can only consist of torture or "FBI-style" questioning, I do not reject the idea that interrogations and interviews where the questioner bonds with the subject are generally more successful.  


I am in the middle of reading an excellent book on this very topic, Practical Aspects of Interview and Interrogation by David E. Zulawski and Douglas Wicklander.  (Full disclosure:  The authors sent me this book for free but have not asked me to plug or review it.)    Their book is not easily summarized but in a nutshell they are strong and effective advocates for the bonding type of interview, not the harsh confrontational method used by many police departments (and prosecutors).  


Among the topics they cover in their book are nonverbal clues to behavior, false confessions,  establishing creditability with a subject and using rationalizations to make it easier for a suspect to confession.  Both men are recognized experts in their field and train police officers and private investigators on the methods they believe have the greatest chance of garnering confessions and incriminating testimony.  


Since many cold cases must now rely on witness testimony, every detective would be wise to read this textbook and put its suggestions into play.  Since I know many of you have lost loved ones in cases that remain unsolved, it can never hurt to see if the detective on your case has heard of the book or the methodology.  Detectives often only get one shot at a suspect or key witness and using the wrong method can forever doom the investigation to the realm of a cold case. 



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