By Scott Kuntz, Deputy Sheriff III, Dane County, Wisconsin, Sheriff’s Office
popular refrain from comedian Rodney Dangerfield is “I don’t get no respect.” Rodney made millions laugh at his never-ending examples of trying to gain acceptance and well…respect.
In the world of modern criminal investigations and police training, proper video evidence collection, and forensic video analysis seem to be in the same predicament. They either fail to get recognized as specialty areas worthy of specialized training, or are rarely treated with well-deserved respect as a legitimate forensic science discipline. Forensic video analysis is the scientific examination, comparison and/or evaluation of video in legal matters.1
The vast majority of today’s felony investigations involve digital multimedia evidence (DME). It describes the video, audio, and metadata that permeate modern society. Closed-circuit video and cellphone video, audio, and GPS data are examples. It is commonplace for criminal investigators to mine Facebook and YouTube to find video and audio evidence of crimes. This article focuses on the challenges encountered when dealing with video evidence.
Would Your Officers Pass the Test?
Do police officers know how to properly identify, preserve, collect, process, report, and present this type of valuable evidence? Is it part of the curriculum at state police recruit academies? Is it taught in most four-year criminal justice programs at colleges and universities? Could most police officers withstand a strenuous cross-examination related to the collection or processing of video evidence?
Is it possible that police officers are just guessing how to handle this fragile type of evidence? If police administrators are honest, the answer to this final question is “Yes.”
Police agencies all over the United States require officers to complete specialized training to perform emergency ordnance disposal, computer examinations, cellphone examinations, canine handling, expert drug recognition, crime scene processing, and so forth.
Police officers and crime scene investigators handling video evidence need to be properly trained as well. Prevailing attitudes in the police community suggest that because most officers are television watchers, DVD users, smartphone owners, and so on, they can properly handle digital video evidence. But this is far from true. To illustrate, a short true/false quiz follows.
- True or false? Infrared lighting at a crime scene ensures accurate reproduction of clothing with synthetic fibers on closed circuit video.
- True or false? The aspect ratio of standard definition television is 4:3.
- True or false? Most closed circuit television (CCTV) digital video recorders (DVRs) utilize FIFO (first in, first out) to manage the storage of data.
- True or false? Lossy data compression is the key to quality video evidence images.
- True or false? Reliability and authenticity do not affect the admissibility of video evidence at trial.
- True or false? Industry standards have made the recovery of CCTV evidence much easier than VHS videotape.
- True or false? Reverse projection at a crime scene can be performed only by the FBI.
- True or false? Video projectors are the best way to show visual evidence to a jury.
The answers provide clues to why digital video evidence is complicated.
- False: Infrared lighting is commonly present at crime scenes that have CCTV cameras. This lighting has a dramatic effect on the way brightness and colors appear on video. Dark objects may look light. Light objects may look dark. Colored objects most likely will not look like they do under natural or incandescent light. Synthetic fibers in clothing and chemicals in hair can affect the appearance of these objects tremendously. If an eyewitness provides a description of a suspect’s clothing based on their observations, it will most certainly not match what is seen on video. This can be a huge problem in catching or convicting a suspect.
|Image under infrared lighting (L); image under visible light (R). The author (pictured) demonstrates the dramatic change infrared lighting has on image appearance.|
- True: Aspect ratio has to do with the ratio of picture width to picture height. Standard definition video is 4:3. High-definition video is 16:9. CCTV video is often inaccurate and recorded at aspect ratios somewhere in between. This error can cause people to look taller or shorter than they really are and look thinner or heavier than they really are. It is essential for the forensic video analyst doing comparison work and trial presentation to correct for aspect-ratio problems.
|Video with correct aspect ratio (L); video that has been vertically stretched (R). The image on the right makes the subject look thinner than he really is.|
- True: Most DVRs do utilize the FIFO method of recording. This means that when the DVR is brand new, plugged in, and begins recording, the hard drive(s) begin filling up with video information. As the hard drive(s) get full, the oldest or first information recorded on the drive gets recorded over first. In other words, the oldest video is the first “out.” If a law enforcement officer is not aware of this concept, valuable CCTV evidence may get erased before it is identified, collected, and preserved.
- False: Lossy data compression is a process utilized by most DVRs to reduce file sizes. Reduced file sizes allow for video to be saved on the DVR for a longer period of time. This is a perceived benefit to the DVR owner because they can keep more video on the DVR. However, it is a detriment to criminal investigation because the lossy data compression reduces the capacity of the video to show details such as license plates, scars, marks, tattoos, and so forth. Video image with heavy compression, which can obscure crucial details such as license plate information.
|Video image with light compression (L); image with heavy compression (R). Heavy compression can obscure crucial details such as license plate information.|
- False: Reliability and authenticity of the video evidence at trial can be a huge hurdle for the attorney introducing the evidence. If the technology of the DVR used to record the video evidence produces inaccurate color, unreliable frame rates, distorted pixel shapes, or inaccurate motion reproduction, the footage derived from the DVR might have problems being admitted as evidence. Especially if a foundational witness cannot adequately explain why the deficiencies exist in the video evidence or what their real meaning is.
- False: A lack of industry-wide standards in the CCTV industry has turned proper recovery of digital video evidence into a research project. Proprietary video codecs and software interfaces have facilitated manufacturer innovation but have also created a barrier to investigators trying to recover and work with the best evidence possible.
- False: The FBI is very good at using this investigative technique. Others who have received proper training can perform this type of work as well. Reverse projection, related to video evidence, is a process of superimposed images or video from a crime scene over live images or video from the same source. Once this is done properly, all sorts of information can be learned about people and objects by examining size, position in the scene, and speed and direction of travel. When performed properly, this is one of the most powerful forensic video techniques available.
- False: Video projectors are probably the most commonly used method for presenting visual evidence to a jury, but in many cases, they are not effective and accurate in how they display that evidence to the jury. Many video projectors are incapable of showing small, critical details in video or still imagery. Many older projectors found in courtrooms cannot accurately display high-definition video. When projectors are used, jurors have to look across a room to see the details in an exhibit. Ambient room lighting and visual distractions in the courtroom can be a significant barrier to seeing key details.
Available Training for Forensic Video
These simple questions scratch the surface of the knowledge needed to properly identify, preserve, collect, process, and present video evidence. Since a large percentage of today’s cases involve video evidence, it is imperative that police agencies worldwide train their officers to understand this area of evidence. What guidance is there for police agencies to get their personnel trained?
- LEVA, Law Enforcement & Emergency Services Video Association–International has a comprehensive list of training classes conducted at the University of Indianapolis, Indiana. Police from all over the world travel to the lab for three- to five-day classes conducted there year-round. From beginner to advanced, LEVA’s training classes prepare students for realworld video evidence interaction. The classes provide a path toward earned certification either as a forensic video technician or as a forensic video analyst. More information can be found at www.leva.org.
- IAI, the International Association for Identification, offers training seminars regarding video evidence. IAI also offers an earned certification as a forensic video examiner. More information can be found at www.theiai.org.
- Quality training is also offered by private companies, some universities, and some technical colleges.
- Quality best practices documents authored by the Scientific Working Group on Imaging Technology (SWGIT) and the Scientific Working Group on Digital Evidence (SWGDE) can be found at www.theiai.org/guidelines.
As methods of criminal investigation adapt to an everchanging world, training should also adapt. One of the most influential changes can occur at the state police academy and police in-service levels. Police academies focus on so many different disciplines for new officers, but not often on the training for this ubiquitous form of evidence. Officers will encounter video evidence constantly. They need to know how to interact with it. It is time to show it some respect. ♦
1The International Association For Identification and The Law Enforcement/Emergency Services Video Association International, Inc., Forensic Imaging And Multi-media Glossary Covering Computer Evidence Recovery (CER), Forensic Audio (FA), Forensic Photography (FP), And Forensic Video (FV), s.v. “forensic video analysis,” www.theiai.org/guidelines/iai-leva/forensic_imaging_multi-media_glossary_v7.pdf (accessed July 26, 2013).
Please cite as:
Scott Kuntz, "Video Evidence Is Everywhere: Training and Respect Are Needed," The Police Chief 80 (September 2013): 38–39.