Evidence Room · Case file
The sound method behind John Cullen’s distance estimates, what an audio forensics expert found, and what peer review would take.
Exhibit A
Crack and thump: estimating where the shot came from by sound
Cullen uses the gap between a bullet’s supersonic crack and the muzzle’s thump to estimate how far away the shot was fired. In July 2026 he revised it, saying what he had measured as the thump was an echo of the crack. His analysis, not a finding; it has not been peer reviewed.
Exhibit B
When a supersonic bullet passes a microphone, its shock wave makes a sharp “crack”. The muzzle blast, the “thump”, follows at the speed of sound. The farther away the gun, the bigger the gap between the two. With the bullet’s speed and the speed of sound, that gap gives an estimated distance. It is physics: the gap can be measured on a waveform, and anyone with the same recording can repeat the measurement.
Exhibit A · Note
Audio forensics professor Robert Maher of Montana State University told CNN he measured about 240 ms between the crack and the pop, which puts the rifle about 153 m from the podium at an assumed 800 m/s (CNN, Sep 11, 2025). John Cullen’s first calculation in September 2025 gave about 143 yards. Later recordings did not add up for him, and in July 2026 he concluded that what he had measured as the thump was echoes of the crack, and that the shot was probably suppressed and fired from farther away.
Exhibit A · Note
Forensic audio is a small field, and the results lean on assumptions: bullet speed, air temperature, where each phone was, and echoes. Peer review would mean publishing the method and the raw audio, independent analysts replicating it, test firings at known distances, and submission to a journal or a body like the Audio Engineering Society, which published Maher’s case study of the 2024 Butler rally audio.
Exhibit A · Reader poll
What do you think of the shock-thump analysis?
One tap, no account. You see the results after you vote.
