Defence lawyers representing Tyler Robinson, who stands accused of murdering conservative activist Charlie Kirk, have requested a postponement of a preliminary hearing scheduled for May.

The legal team claims it requires additional time to investigate suggestions that a bullet recovered during the autopsy does not correspond with the rifle found close to the crime scene.

In recent court filings, Mr Robinson’s defence highlighted an analysis from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), a federal law enforcement agency. This analysis reportedly failed to establish a conclusive link between a bullet fragment retrieved during the post-mortem examination and the rifle located near the scene. Although the ATF’s report has been kept private, attorneys have cited snippets in other public documents, confirming its inconclusive findings. The Federal Bureau of Investigation (FBI) is now conducting further tests, according to court papers.

The success of a forensic ballistics analysis largely depends on the size and condition of the bullet fragments. Experts are looking for unique, microscopic markings that are left on a bullet as it passes through the gun’s barrel. The scratches are like fingerprints in that no two firearms make identical markings.

The defense said in its motion that it may try to use the analysis to clear Robinson of blame during the preliminary hearing, while prosecutors aim to show they have enough evidence against him to proceed with a trial.

Prosecutors intend to seek the death penalty for Robinson, 22, who is charged with aggravated murder in the Sept. 10 shooting of the conservative activist on the Utah Valley University campus in Orem. Robinson has not yet entered a plea.

Prosecutors have said DNA consistent with Robinson’s was found on the trigger of the rifle, the fired cartridge casing and two unfired cartridges. Defense attorneys note that forensic reports indicate multiple people’s DNA was found on some items, which they say requires a more complex analysis.

Robinson reportedly texted his romantic partner that he targeted Kirk because he “had enough of his hatred,” prosecutors have said.

Robinson is due back in court April 17 for a hearing on a defense motion to ban cameras from the courtroom.