The mystery surrounding the death of conservative activist Charlie Kirk has deepened with a major new development. Defence attorneys for Tyler Robinson, the 22-year-old accused gunman, say that the bullet recovered from Kirk does not match the rifle allegedly used in the killing.

Robinson faces capital murder charges and could receive the death penalty for the fatal shooting on September 10 at Utah Valley University. Prosecutors say he drove three hours to the campus to carry out the attack.

Defence challenges key evidence in Charlie Kirk murder case

According to AP, Robinson’s team pointed to a report from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), which studied a bullet fragment recovered during Kirk’s autopsy. According to the defence, the analysis could not definitively link the fragment to the rifle found near the scene.

The ATF report has not been made public, but attorneys have quoted parts of it in other filings, confirming the results were inconclusive. Court documents show the FBI is now running additional tests on the bullet.

Experts say forensic ballistics depends heavily on the size and condition of fragments. They look for tiny, unique markings left on a bullet as it travels through a gun barrel. These markings act like fingerprints, since no two guns leave identical scratches.

Defence and prosecution prepare their cases

The defence told the court that it might use the ballistics analysis to show Robinson is not responsible for the shooting during the preliminary hearing. Prosecutors, meanwhile, want to prove there is enough evidence to move forward to a trial.

Prosecutors are planning to seek the death penalty for Robinson, 22, who is charged with aggravated murder for the shooting of Kirk on September 10 at Utah Valley University in Orem. Robinson has not entered a plea yet.

Authorities, however,  say DNA matching Robinson’s was found on the rifle’s trigger, the fired cartridge casing, and two unfired cartridges. Defence attorneys point out that some forensic reports show DNA from multiple people on certain items, which they say makes the evidence more complicated. Prosecutors have also revealed that Robinson texted his romantic partner, saying he targeted Kirk because he “had had enough of his hatred.”

Robinson is scheduled to return to court on April 17 for a hearing on a defense motion to ban cameras from the courtroom.