Category : Uncategorized

Expert Swimmer Drowns During Underwater Workout

Swimming Pool Drownings

Tom Griffiths, Ed.D., Aquatic Safety Expert

In a large 50-meter swimming pool, an expert swimmer in the military drowned while “dolphining” for extended periods of time. He worked out strenuously on the surface prior to his underwater exercises, so it is likely that he depleted his oxygen and carbon dioxide stores prior to his underwater swims. This was a classic Shallow Water Blackout scenario, where a good swimmer overexerts themself in the water and then holds their breath for long periods of time repetitively underwater.

Dolphining is an underwater kicking exercise where the swimmer, wearing fins, will swim many underwater lengths while performing an up and down dolphin kick. During dolphining, the expert swimmer fell unconscious and the lifeguards on duty missed recognizing him underwater, which is not difficult to do. When someone quietly slips beneath the surface, the water hides and suffocates its victims. In addition, lifeguards tend not to watch these underwater swimmers because they are such superior swimmers, often stronger swimmers than the lifeguards on duty. Lifeguards likewise wrongly believe good swimmers do not drown.

In this case the family of the deceased blamed the lifeguards for their inattentiveness. Conversely, the defendants blamed the underwater swimmer because he should have known competitive and repetitive underwater swimming is dangerous and deadly.

Lessons Learned: ALL swimming pools MUST ban extreme underwater swimming and prolonged breath-holding. Lifeguards must be trained to enforce this vitally important rule.

Tom Griffiths, Ed.D., Aquatic Safety Expert with DJS Associates, Inc., can be reached via email at or via phone at 215-659-2010.

The Light at the End of the Tunnel

James R. Schmidt, Jr., BSME, Collision Reconstruction Engineering Analyst

Okay, if it’s not speed from video that I’m writing about, then it’s sun glare!

Sun Glare 1

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Apple’s Health Application

Apple iPhone

Timothy R. Primrose, Mobile Forensic Analyst

Apple’s health application monitors and documents a user’s day to day activity in detail. Some data is collected by the iPhone, while other data can be collected from a synced Apple watch or input directly by the user. These datatypes include steps, body measurements, menstrual cycle tracking, hearing, heart rate, mindfulness, mobility, nutrition, respiratory, sleep, vitals, and other user input data such as blood glucose and inhaler usage.

From a forensic standpoint, you might not think that health data can help decipher the events that unfolded in a given situation; however, some of these datatypes can be utilized. The hearing datatype proved useful in one of our recent cases.

The purpose of the hearing category in Apple’s health application is to monitor headphone audio levels to ensure that the user’s ears are exposed to a healthy level of sound decibels to prevent hearing issues caused by extended exposure to loud audio. In the image below you can see the audio levels that a user’s headphones were set to, the timeframe that they used their headphones, the media source of the audio, and even the type of headphones utilized. Users can view their listening history that Apple has recorded within the health application.

Apple Recorded Data

How was hearing data useful in a forensic investigation? A vehicle operator was traveling at the posted speed limit of 45 mph when a woman suddenly stepped out in front of him. He did not have enough time to stop and unfortunately the woman did not survive. The woman had headphones in and was reportedly looking at her phone when she stepped into oncoming traffic. Data extracted from her cell phone showed that the pedestrian had the YouTube application open leading up to and at the time of the incident. Audio level data recorded by Apple’s health application showed that the user’s device was outputting an audio level of 150 dB. This volume level would have prevented the woman from hearing any approaching vehicles or the buzz of traffic. Seeing that the YouTube application was open and not an application such as Pandora or Spotify aids the vehicle operator’s story that the pedestrian was looking at her phone and distracted from where she was walking.

Health data can be utilized for more than what Apple intended. Even if you do not plan on using this information for a case, check it out for yourself and make sure your audio levels are safe.

Timothy R. Primrose, Mobile Forensic Analyst with DJS Associates, Inc., can be reached via email at or via phone at 215-659-2010.

Perception-Reaction Time

Reaction Time

Robert T. Lynch, PE, Principal Collision Reconstruction Engineer

A colleague recently sent me a link to an online game to test one’s reaction time (see link below). The game simulates a (right-hand drive) vehicle traveling down a straight, hilly roadway with trees, signs, and deer to the sides of the roadway. When the player sees a red stop sign with a hand on it, they are to click the mouse or press any key on the keyboard to stop the simulation. Reaction time, the time between when the stop sign is presented on the screen and when the mouse or keyboard is clicked/pressed, is then compared to how 2,000 people above the age of 18 performed in this same simulation.

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School Bullying Litigation

School Bullying Expert Witness

Bruce Ira Levenberg, BS, MS, PD, SAS, SDA, School Bullying Expert

Some estimate that as much 90% of students in public schools have been harassed or bullied. According to the National Education Association (NEA), over 160,000 children refuse to go to school each day for fear of being bullied. Although public schools have strict protocols for reporting and investigation, only one in five (as estimated by of those occurrences get reported.

Bullying is unwanted behavior that is intended to harm others, aggressive in nature, characterized by a real or perceived imbalance of power, is usually marked by repeated behaviors and/or incidents, or that have the potential to be repeated over time. Categories of bullying include: Physical (physical actions), Verbal (cruel words, statements and/or name calling) Emotional/Social/Sexual (often in combination), and Cyber (using the internet for name calling, teasing and/or intimidation). All these actions can be done singularly or in combination by the bully aggressor in order to gain dominance and control over the bully victim.

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North American Commercial Vehicle Safety Alliance Update


Leslie Lovre-King, Technical Assistant

Every year, the North American Commercial Vehicle Safety Alliance (CVSA) conducts a coordinated, multi-day event targeting commercial trucks, trailers, and passenger-carrying vehicles. The purpose is to promote safety awareness within the commercial trucking industry and to ensure regulatory compliance. Each year, the CVSA selects one or two key safety metrics to highlight during its annual event. Data collected during these annual events help identify industry-wide safety deficiencies and help establish the focus of future events. International Roadcheck 2021 will focus on driver hours-of-service and vehicle lighting.

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