Posts Tagged ‘Evidence’
All forensic experts write reports. Some reports are better than others. What goes into a ‘better than other’ forensic report? Depending on the forensic investigation, opening the forensic report with the credibility building language is an important starting point. Here is a sample of how I open my audio forensic reports:
I am an audio forensic expert and have been practicing for 29+ years. I have testified in several courts throughout the United States and worked on various international cases. My forensic practices includeaudio authentication, restoration and voice identification.
The next step in the forensic report is to include the evidence you were provided by your client to forensically examine, as well as what you were asked to do. This paragraph must be documented and described in detail. Here is a sample of how I draft this section:
On or about March, 25, 2011 I received a CD from your office that contains a 911 call recording. You asked that I investigate the recording to determine if it contains one or two voices at the scene of the crime.
I listened to the CD and heard the initial voice that spoke and the second questionable voice in the background, noting that it sounded different from the first voice. I suggested making arrangements to create an exact exemplar of the suspect for comparison purposes in this forensic investigation.
On Tuesday, April 23, you and I arranged to create an exemplar of the suspect’s voice to comparewith the initial 911 call first voice. The exemplar was created using as much of the same electronics as possible that were used in the original 911 call recording. Also featured in the exemplar were the exact cell phone and the same person that placed the original 911 call.
In addition, we also recorded exemplars of other persons who could have made this 911 call for comparisonpurposes in a voice identification line up.
This above outline is an example. Much of the language might not make sense but the text still exemplifies the message I am communicating about audio forensic reports.
The next part includes your investigation; what you did as an audio forensic expert and the opinions you arrived at. This investigative process must list all activity, testing and the software programs, hardware and other tools, scientifically describing in detail all tests so that another forensic expert with similar qualifications can recreate your testing and arrive at conclusions.
In a case where the opposite side in the litigation has retained a forensic expert, that forensic expert will want to review your investigation and findings to determine how to strategize the court proceeding based on this information as well as your opinion. I have worked on cases where the forensics experts were disagreeing with each other before the trial, and others where forensic experts were disqualified before trial. This is why forensic report writing is crucial and one of the most critical parts of any forensic investigation.
The fourth component in the forensic report is the expert’s conclusions; often times this conclusion is ‘based on a reasonable degree of scientific certainty’. The audio forensic expert reports the truth about the evidence in question or another characteristic in question about the audio evidence. The conclusion is a statement of scientific fact and opinions expressed about the conclusion of scientific fact must be presented in simple English for all triers of fact and other expert witnesses to easily understand.
When the forensic report is submitted, it should also include any work product, sub files and the most recent CV (curriculum Vita). If the case is older, chances are the expert has updated their CV since beginning the forensic investigation.
If you have an audio forensic concern and would like more information about the investigating process with regard to report writing, call or write for a pro bono consultation.
How reliable are audio forensic procedures in the legal system? A student recently asked me that and asked about some of the ins and outs of a career in audio forensics. The student’s specific questions are below and are followed by my answers.
1. How often is speech-based evidence used in court? It’s used very often. Voice identification evidence helps a court to identify people involved in a case and put the puzzle pieces of a case together. Furthermore, voice identification can also sometimes provide substantial enough evidence to cause people to be convicted or released.
Is it a common or rare occurrence? Our business has grown significantly, so I would say that audio forensic procedures in the legal system are common.
2. Is voice identification a lengthy process? It can take up to 4 hours for the average case. This includes 3 types of examination. Audio forensic experts visually examine the sound wave, comparing the evidence and an exemplar (a voice sample of the accused). Next, Audio forensic experts electronically measure the evidence, which is then compared to the exemplar. Finally, and most importantly, audio forensic experts critically listen to compare how the words are spoken and pronounced in the evidence and the exemplar.
3. Are there any factors which can create problems when dealing with a recording? Yes, difference in age between the recording in question and the creation of the exemplar creates problems. People’s voices change with the passing of time. One of the nationally accepted standards for comparing voices is that the voice samples must not be more than six (6) years apart.
4. Is voice identification considered to be reliable within the legal system? YES. However, it’s argued more in some states than others. The forensic expert must carefully examine all scientific evidence and follow procedures. Both law enforcement and defendants seek assistance from audio forensic experts.
An expert witness is a person who by virtue of education, training, skill, or experience, is believed to have expertise and specialized knowledge in a particular subject. His or her expertise is beyond that of the average person, sufficient that others may officially and legally rely upon the witness’s specialized (scientific, technical or other) opinion about their area of expertise. The expert witness will render an opinion (also known as the expert opinion) about the forensic evidence presented.
Expert witnesses help lawyers develop strategies on how the evidence in question should be argued or presented in court. Often time’s audio evidence may not be original or genuine and should be closely examined by the audio forensic expert to authenticate the evidence or strategize with the lawyer on how to write the motion to have the case dismissed or audio evidence removed from the case.
Expert witnesses have a complete understanding of legal proceedings and can be a huge aid to the plaintiff, defendant and courts when a piece of audio evidence is part of the legal case. Defendants who are facing serious charges especially need to seek the guidance and advice of an audio forensic expert. Plaintiffs who want to establish a solid case should seek the help of an audio forensic expert to authenticate their audio evidence prior to entering the court room. Expert witnesses are valuable resources to courts and other legal professionals.