Photo Appears to Capture Path of Bullet Used in Assassination Attempt

In documenting the Pennsylvania campaign rally on Saturday afternoon that turned into an attempt on a former president’s life, Doug Mills, a veteran New York Times photographer, appeared to capture the image of a bullet streaking past former President Donald J. Trump’s head.

That is the assessment of Michael Harrigan, a retired F.B.I. special agent who spent 22 years in the bureau.

“It absolutely could be showing the displacement of air due to a projectile,” Mr. Harrigan said in an interview on Saturday night after reviewing the high-resolution images that Mr. Mills filed from the rally. “The angle seems a bit low to have passed through his ear, but not impossible if the gunman fired multiple rounds.”

Simple ballistic math showed that capturing a bullet as Mr. Mills likely did in a photo was possible, Mr. Harrigan said.

Mr. Mills was using a Sony digital camera capable of capturing images at up to 30 frames per second. He took these photos with a shutter speed of 1/8,000th of a second — extremely fast by industry standards.

The other factor is the speed of the bullet from the firearm. On Saturday law enforcement authorities recovered an AR-15-type semiautomatic rifle at the scene from a deceased white man they believe was the gunman.

“If the gunman was firing an AR-15-style rifle, the .223-caliber or 5.56-millimeter bullets they use travel at roughly 3,200 feet per second when they leave the weapon’s muzzle,’’ Mr. Harrigan said. “And with a 1/8,000th of a second shutter speed, this would allow the bullet to travel approximately four-tenths of a foot while the shutter is open.”

“Most cameras used to capture images of bullets in flight are using extremely high speed specialty cameras not normally utilized for regular photography,