Two Cases Utilizing Audio Enhancement
Audio can be a key piece of evidence in building a case. But obtaining audio that is both clear, and admissible in court can be tricky. Every state is different in terms of audio admissibility in court. Federal law (18 U.S.C. § 2511) requires one-party consent, which means that you can legally record a conversation as long as you are a part of it. However, if you are not party to the conversation, at least one person must consent to being recorded in order for the recording to be legal. Most states have similar laws to the federal law, however, some states have enacted two-party consent laws. This means that all parties present must consent to being recorded, except in the case that all parties reasonably should have expected to be recorded.
In the following cases, let’s assume we are operating under the federal law one-party consent rule.
A. Prosecution
There are many places that audio evidence may be pulled from, and then need to be enhanced. Let’s look at a theoretical homicide case.
The defendants are two teenagers who are being accused of orchestrating and committing the murder of a classmate. There is limited physical evidence, so the state is trying to compile as much digital evidence as possible to make sure they have a strong case against them. They gain access to the defendant’s phones, and perform physical extractions of each device. On one of the defendant’s devices, they find saved Snapchat videos of a party prior to the classmate’s death. The videos appear to be taken by someone other than the defendants, as they are seen talking in the background. Their voices are distant, and the noise of the party makes it difficult to hear what they are saying. Digital forensics experts are able to isolate their voices and pick up on their conversation. They hear them discussing the classmate in a negative light and alluding to potential plans. This evidence is then used by the prosecution against the defendants in building their case.
B. Defense
Audio evidence can prove to be exculpatory, but it has to be clear first. Let’s examine a theoretical case in which the defendant’s legal team used audio enhancement to tear down pieces of the prosecution’s case.
The defendant has a case brought against them of assaulting a coworker. The plaintiff’s legal team is trying to paint a negative image of the defendant. They discover that the defendant was brought in for possession of illegal substances during a routine traffic stop months prior to the alleged assault. This incident is key to their case against the defendant.
The defendant tells his legal team that they believe they were brought in wrongfully, as they did not give the officer permission to search their vehicle and there was no probable cause. The defendant’s legal team obtains the body cam footage of the incident, but the audio is muddled from traffic driving by. Digital forensics experts are able to enhance the audio by isolating their voices, and hear the officer asking to search the vehicle and the defendant clearly saying no. The officer had pulled the defendant over for speeding, and there were no signs of anything suspicious from the defendant. This audio helped to show that the substances had been found illegally, violating the defendant’s fourth amendment, and could not be used as evidence in the court of law. This meant that their previous arrest could not be used by the plaintiff’s team to illustrate his alleged character.