Forensic analysis suggests that as many as three weapons were fired at the Trump rally in Butler, Pennsylvania on Saturday.
The FBI said Sunday that the shooter
acted alone.
The first three shots were consistent with alleged weapon A, the next five were consistent with alleged weapon B, and the final "acoustic impulse" was emitted by a possible weapon C, per audio analysis by Catalin Grigoras, director of the National Center for Media Forensics at the University of Colorado in Denver, and Cole Whitecotton, Senior Professional Research Associate at the same institution.
Audio analysis
has also confirmed that the gunman was about 360 to 393 feet from the podium, according to forensics expert Robert Maher.
This conclusion aligns with
CNN's analysis that the gunman was on a rooftop 393 to 492 feet from the podium when shots rang out.
The shots exemplify a "crack-pop" sequence, typical when a supersonic bullet passes a microphone, before the "arrival of the corresponding muzzle blast sound," Maher, who teaches audio forensics at Montana State University, told CNN.
The time between these markers places the shooter 110 to 120 meters from the microphone, Maher said, assuming the bullet is moving at an average speed of 800 to 1,000 meters per second, the equivalent of 2,600 to 3,280 feet per second.
