Explaining Forensic Audio (Part 1)

The concept of forensic audio investigation may have become popular in recent years along with the forensic sciences in general but it’s been in practice since World War II. With audio use in full swing for radio transmissions across long distances, scientists were trying to identify the voices of their enemies among the many radio broadcasts that took place on open frequencies. The work done in forensic audio investigation today is based on the pioneer work of those scientists.

Specifically, forensic audio has to do with any type of audio of an evidentiary nature. In modern cases, law enforcement or other legal professionals (e.g., defense attorneys and prosecutors) will turn to a forensic audio examiner to perform any one of a number of services where audio is concerned.

In many cases these specialists are hired on a contract basis.

While the most common Hollywood portrayal is audio enhancement with a few twists of a knob (if only it were so easy) there is a great deal of work that can be done:

  • Audio Enhancement – the most common and offered by just about every forensic audio company you can find.
  • Audio Authentication – geared toward tape and digital formats
  • Forensic Transcription
  • Speaker Identification

There are also a number of other services or procedures that can be classified in their own right as a specialty process or “miscellaneous” in terms of categorization. This article will focus specifically on Audio Enhancement and Authentication.

Audio Enhancement
Audio enhancement is the most common and well known service where forensic audio is concerned.

It’s not likely that one can take a garbled and mangled inaudible conversation and “tweak it” to produce clear speech that is intelligible. While audio enhancement isn’t specifically focused on speech, that is usually the intent behind cleaning up or enhancing audio for legal purposes. It’s a means of reducing or filtering out unwanted noise from a poor recording in order to clear up the speech that’s covered with noise or is a victim of poor recording methods.

A forensic examiner is not a miracle worker however, and while modern software and equipment has provided a variety of tools to improve the quality of speech in a recording, there are still limitations. When it comes to enhancing speech, you can’t fix something that’s just not there. If the recording doesn’t contain the robust elements of someone’s speech, and the equipment only picked up bits of a word or phrase, there is no magic software to fill in the blanks. Enhancement techniques can sometimes have fantastic results with intelligibility, but more often would be a disappointment to the layperson.

In terms of speech enhancement, an examiner can offer critical listening in combination with forensic transcription and speech decoding methods to help identify and discern what is being said. Again, technology can only do so much so an examiner with linguistics and phonetics experience is usually best for the job. However, if the speech waveform isn’t picked up by the recording device or is masked by noises of the same frequency range, he won’t be able to decipher the speech.

Forensic audio enhancement sometimes simply involves increasing the volume of a whisper from a suspect where traditional playback – even at high volume – can’t help an individual understand the utterance. Audio enhancement offers the most benefit in situations where noise can be eliminated or at least reduced so as not to distract the listener from the speech. Enhancement techniques are quite good at getting rid of electronic buzzing or hum and other noises such as tape hiss, the crackles and pops of a phonograph record or the beeping of a backing truck, open car door, low battery warning of a fire detector, etc. Enhancement used in this way is often called improving the listenability of the recording. Unintelligible speech isn’t made intelligible but the recording is easier on the ears.

Audio Authentication
Authenticity is an important part of legal matters where evidence is concerned. This is especially true when it comes to audio that is or will be entered into evidence in a criminal or civil matter. As technology advances, it becomes progressively easier for an individual to tamper with a recording.

Audio authentication – either involving tape authentication or digital file authentication – is a way to ensure that the audio being utilized as evidence has not been tampered with in some way.

Not only will a forensic audio examiner use software to examine the actual recording, but authentication involves examining the physical tape itself and its casing.

This includes:

  • Checking the tape for splices
  • Examining the tape’s plastic shell to check for prying or disassembly
  • A process of examining the tape call magnetic development

Magnetic development involves using a magnetic liquid called ferrofluid in the examination of audio or video tape. The ferrofluid allows the forensic examiner to see the magnetic patterns on a tape. The types of things the audio engineer would look for include magnetic signatures left by stopping, pausing and starting the recording process. It can also be possible to tell if the tape has been recorded over or simply erased and left blank.

Newer software provides an edge when it comes to detecting authenticity in audio as it looks into variances that could lead to falsification of a recording – particular in tape recordings:

  • Equipment noise – hums, pops, varying pitch in inconsistent forms over the whole of the recording
  • Fading – Any gradual or sudden decline in volume that effects the interpretation of noise or dialogue. If the sound cuts out completely that becomes a gap in the recording
  • Gaps – Any segment where there is a change (often unexplained) in the content or context of an audio recording. A perfect example of this is the infamous Watergate recording where there is an 18 and ½ minute gap in the recorded audio that was later discovered to be an overlaid recording of electrical interference.
  • Transients – These are clicks or pops and other “attack” sounds within a recording and may signify that there has been a splice or some other alteration to the recording

There are a number of methods that are used to authenticate a recording, checking it specifically for originality. An obvious and important tool that a forensic audio examiner has is the ear. Critical listening affords a great deal of benefit and it takes training and experience to know what to listen for while playing a track over and over.

In some cases, an examiner may have to run through a section of audio many dozens of times. They examine bits of a conversation or sections of a recording to fully understand the sounds – including both foreground and background sounds. If something stands out the examiner will further investigate that specific segment using their trained ear to discern if the recorded event is authentic or not.

Beyond listening, the examiner utilizes physical inspection as well as spectrum and waveform analysis to visually inspect the quality and construct of a specific piece of audio. All of these methods come together allowing the examiner to certify the authenticity of a tape recording.

Things become more difficult when a recording is made using a digital recorder that creates audio files such as.wav or.mp3. While many of the above methods may be useful with a recording that originated as a digital file, it is somewhat easy for a knowledgeable person to edit the file without leaving any known sign of doing so.

One promising method of digital authentication is the use of ENF (electric network frequency) data. Whenever someone is recording while plugged into an electrical outlet or using a battery operated device within an ENF magnetic field, their recording will include a 50Hz or 60Hz (depending on country) waveform signature. This signature can be compared to an ENF database to possibly determine where and when the recording was made, whether it’s an original or a copy, or whether it was edited or altered in anyway. Digital audio authenticity examination, and more specifically the use of ENF, is in its infancy and has a way to go before forensic audio examiners reach the level of sophistication that has been achieved with authentication of analog tape recordings.

The use of software to determine authenticity and enhance audio is just the beginning when it comes to forensic audio. Depending on the situation, additional specialty services or skills may need to be applied such as speaker identification and the analysis of gunshot sounds to determine if more than one weapon was used, which type of firearm was used, or the sequence of the shots fired. Forensic audio is a robust trade that encompasses a number of specialists who work together to bring clarity through the study and examination of audio.

Online Computer Forensics

Online computer forensics covers a wide area of data investigation and retrieval. It can involve internet crimes, email abuse and trading of intellectual property, to name a few.

Hackers aren’t the only ones committing online crimes these days. Computer forensics analysts are being called on in large numbers to investigate company employees and crime in the work place.

Many corporations are hiring teams of online computer forensics experts to track employees and their daily habits. It can be minor cases such as internet or email abuse causing wasted hours on the clock, or it can be a more critical crime such as employees selling intellectual property or using it to operate a competing business on the side.

Another area where computer forensics is extremely useful is when investigating criminal cases. There are many people out there participating in illegal online activities, such as child pornography sites and trading of information. It’s good that our system puts a high level of importance on bringing these people to justice and shutting down these sites and digital forensics are what makes it possible to find these people and prosecute them to the fullest extent of the law. These practices are not tolerated and with the proper input from an online computer forensics expert, people participating in these unlawful practices can easily be found guilty and put behind bars.

It’s best to gain access to a computer before anyone has a chance to destroy evidence. But even if an individual knows they might be investigated it is very possible to retrieve any information they try to delete. It’s also very easy to monitor their actions through computer or phone spying software.

Cell phones are very common these days and with this technology comes a new area where computer forensics can be utilized. A lot of illegal activity happens over cell phones. Text messaging, picture messaging and basic phone calls can contain information that is highly relevant if trying to prosecute a person of a cyber crime. Phones these days are basically small computers that can send and receive the same data as most computers. It’s important for computer forensics experts to keep up with this changing technology and be able to handle any scenario thrown their way.

Cell phone spyware is new software that allows anyone to tap into a phone’s calls, messaging and internet usage. With a simple application put onto a phone you can track everything that phone does. This can be good and bad. It’s not very settling to know that anyone can track everything you do on your phone, but from a computer forensics standpoint, this is a valuable tool that could possibly bring severe criminals to justice.

Online computer forensics is all about keeping up with the criminals and their practices. As they learn new ways to hack into systems or run email scams, it’s important that digital forensics experts keep up and are able to use their knowledge to solve crimes and keep our internet safe.

Forensic Genealogy – Dead Men Do Tell Tales

While the Bermuda Triangle is the end of a journey, the Forensic Genealogy Research Triangle represents the beginning of an ancestral research journey. History, Geography, and DNA create the perfect equilateral triangle of forensic research. If you must supply documentation for a legal case that requires source citations or written reports, you are now entering the world of forensic genealogy.

When I set out to research this article, I was a tad surprised to see forensic genealogy described as a “modern” approach to family research, as though it were invented yesterday. The practice has been around for quite some time. Only recently has it gotten a sexy name and the respect and appreciation it deserves.

I have heard forensic genealogy described as “the study of kinship and identity as it pertains to the law.” That’s a good definition, but I prefer professional genealogist Megan Smolenyak’s description – “reverse genealogy” – because in many forensic cases, you begin with the deceased and you look for the living, compared to conventional genealogy, which usually starts with the living and looks for the deceased. (Ms. Smolenyak is the author of Trace Your Roots with DNA.)

A lot of forensic research is figured out by available documentation with science and technology mixed in. The three most important sources of this area of study are:

1) Photo analysis

2) Database mining

3) DNA analysis

Research Formula:
Forensic techniques + conventional research = forensic genealogy

In other words, forensic genealogy takes the facts discovered by conventional genealogy and weaves them together to give you an entire picture. It is a relatively modern approach to family research for the legal profession and law enforcement. I’ve heard it referred to as “CSI Meets Roots.”

One of the most common uses for forensic genealogy is to locate missing heirs to estates. This is not a new practice. In fact, Laurie Thompson, a highly respected former Regent of a New York City Daughters of the American Revolution (DAR) chapter, provided genealogy research to the FBI and other law enforcement agencies, in addition to finding next of kin, for more than 40 years. She didn’t have the luxury of online databases; she did it the hardcopy way. The answer to a case may be found in a city directory or in hospital or cemetery records. So “high-tech” is not necessary in forensic genealogy, but it sure does help. Where the high-technology comes in handy is with the DNA testing; but in the end, the science must be supported by the analyses of photos and documents.

A short list of areas that are served by forensic genealogy includes:

• Probate and estate cases

• Guardianship cases (next of kin)

• Civil pension, Social Security, or veteran benefits

• Land issues

Experts in the Field

Colleen Fitzpatrick

Fitpatrick is described as a “real-life CSI detective who has helped crack the most compelling mysteries of our time.” Currently, she is a consulting genealogist for the Armed Forces DNA Identification Laboratory (AFDIL).

Boasting a PhD in nuclear physics, as well as an MS in physics from Duke University in Durham, North Carolina, Colleen Fitzpatrick founded her own high-tech optics company (Rice Systems) in her garage. She subsequently contracted with NASA, the US Department of Defense, the National Institutes of Health (NIH), and the National Science Foundation, as well as other civil and government agencies.

Fitzpatrick is the author of several best-selling books on genealogy, including Forensic Genealogy, which is considered “The Reference” for the entire profession. Dick Eastman, renowned genealogist and host of his own website Eastman’s Online Genealogy Newsletter, highly recommends her book. Other books by Fitzpatrick include DNA and Genealogy (2005) and Dead Horse Investigation: Forensic Photo Analysis for Everyone, among others.

Dee Dee King

An expert in the field of forensic genealogy, Dee Dee King serves on the board of the Council for the Advancement of Forensic Genealogy (CAFG);a professional business league. The Council’s website offers valuable research resources, including links to probate codes, bar associations, state rules of evidence, genealogist/attorney relationships, and more. The Council also offers classes, and those who pass the course receive a Forensic Genealogy Institute Certificate of Completion.

Forensic genealogy in short is research, analysis, and reporting in cases with legal implications. It’s mining for research gold, using creative resources outside the realm of conventional genealogy research. It is applying scientific processes to traditional research to arrive at an answer. It is the dead speaking from the grave… “where are you?” Do you hear dead people speaking? If you do, forensic genealogy may be for you.