A significant development has emerged in the investigation into the murder of Charlie Kirk, with revelations concerning bullet fragments from the crime scene captivating public attention on Thursday.
In a court session, a federal firearms specialist testified that she could not conclusively determine whether the bullets in question had been fired from the rifle allegedly used by Tyler Robinson, according to prosecutors.
This testimony follows weeks of intense speculation, spurred by court documents indicating that the ballistics evidence might weaken the prosecution’s case against the 23-year-old defendant.
Robinson stands accused of killing Kirk while he was speaking to attendees at Utah Valley University on September 10, 2025.
On Thursday, the ballistics expert emphasized that her analysis did not exclude the rifle as the weapon used; however, the findings were not definitive either.
‘My conclusion is inconclusive… I am unable to say one way or another,’ Samantha Karner, from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), testified under questioning from Robinson’s attorneys.
Karner appeared during a preliminary hearing that will determine whether Robinson will stand trial on an aggravated murder charge. Prosecutors are seeking the death penalty.
The defense has repeatedly pointed to the ATF’s ballistics findings in an effort to challenge the strength of the state’s case.
ATF firearms examiner Samantha Karner testified that ballistics testing on bullet fragments recovered from Charlie Kirk’s body was inconclusive
An image of a cartridge engraved with the word ‘Catch!’ is displayed during a preliminary hearing for Tyler Robinson, the Utah man accused of fatally shooting Charlie Kirk
Bullet fragments are shown on a screen during in court. Karner told the court she could not determine whether the bullet fragments were fired from the rifle linked to Tyler Robinson
Earlier this year, Robinson’s attorneys cited an ATF report that stated investigators were unable to identify a bullet jacket fragment recovered during Kirk’s autopsy as having been fired by the rifle recovered by authorities.
That filing prompted widespread claims online the bullet ‘did not match’ the suspected murder weapon.
Karner’s testimony, however, emphasized that the examination simply could not reach a definitive conclusion.
Defense attorney Michael Burt pressed the firearms examiner over whether investigators could exclude the recovered rifle as the weapon that fired the fatal shot.
‘Saying anything but inconclusive was inappropriate,’ Karner replied.
Firearms experts have previously said an inconclusive finding is not unusual, particularly when only damaged bullet fragments are available for examination.
According to experts interviewed by PolitiFact, microscopic markings left on bullets can be too distorted after impact to allow examiners to definitively identify, or eliminate, a particular firearm.
Christopher Ballard, a spokesperson for the Utah County Attorney’s Office and a member of the prosecution team, previously said an inconclusive finding ‘does not mean that the rifle did not fire the bullet.’
‘There just aren’t enough marks on the fragment to make a conclusion one way or the other as to whether the bullet fragment was fired by the particular rifle,’ Ballard said.
Charlie Kirk hands out hats before speaking at Utah Valley University in Orem, Utah, on September 10, 2025, shortly before he was killed
Bullet fragments are shown on a screen during a preliminary hearing for Tyler Robinson
The hearing will determine whether Tyler Robinson, pictured, will stand trial on an aggravated murder charge. Prosecutors are seeking the death penalty
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Stephanie Walcott, an assistant professor in the Department of Forensic Science at Virginia Commonwealth University, also said it would be ‘extremely misleading’ to interpret an inconclusive finding as proof the rifle was not involved.
The ballistics evidence represents only one part of the state’s case against Robinson.
Prosecutors allege Robinson stole his grandfather’s rifle and engraved taunting slogans onto ammunition before the shooting, traveled to Utah Valley University and fired the fatal shot from a rooftop overlooking Kirk’s event.
Authorities contend Robinson wrapped the rifle in a towel before hiding it in a wooded area near campus, later attempting to retrieve it.
Investigators say Robinson’s DNA was recovered from the rifle’s trigger, other parts of the firearm, the fired cartridge casing, two unfired rounds and the towel used to conceal the weapon.
Earlier on Thursday, jurors-in-waiting heard additional evidence that prosecutors say further ties Robinson to the killing.
Video of Robinson’s roommate and former romantic partner, Lance Twiggs, was played in court after a lengthy legal fight over whether portions should remain sealed.
An image of a rifle that prosecutors say was recovered by investigators near Utah Valley University is displayed during a preliminary hearing for Tyler Robinson
Tyler Robinson, far left, who is accused of the fatal shooting of Charlie Kirk, sits as Judge Tony Graf confers with attorneys during his preliminary hearing in Provo, Utah
Charlie Kirk’s parents, Kathryn, left, and Robert Kirk leave the Fourth District Courthouse in Provo, Utah, on Thursday
Twiggs, who received limited immunity for his statements, told investigators Robinson broke down in tears inside their southern Utah apartment the day after the shooting.
According to Twiggs, Robinson said he ‘wishes he hadn’t done it.’
Investigators also revealed that roughly an hour before surrendering to authorities, Robinson allegedly posted a message in a Discord chat room reading: ‘it was me at UVU yesterday.’
Prosecutors further allege Robinson left a handwritten note for Twiggs stating: ‘I had the opportunity to take out Charlie Kirk, and I took it.’
The note continued: ‘I wish we could have lived in a world where this did not feel necessary.’
Additional text messages shown in court allegedly captured Robinson worrying about fingerprints being left on his grandfather’s rifle and discussing ammunition engraved with messages including ‘Hey Fascist! CATCH!’ and ‘If you Read This, You Are GAY.’
Twiggs also testified that weeks before the shooting Robinson had asked to borrow a Dremel tool to engrave shell casings.
At the time, Twiggs believed Robinson intended to decorate ammunition for an upcoming hunting trip.
Kirk’s widow, Erika, had urged the court to release Twiggs’ interview in full, arguing that withholding portions would only fuel conspiracy theories surrounding her husband’s death.
The .30-06-caliber bolt-action hunting rifle recovered near the scene of Charlie Kirk’s fatal shooting at Utah Valley University
A photo which prosecutors say shows a text message exchange between Tyler Robinson, who is accused in the fatal shooting of Charlie Kirk, and Robinson’s roommate and romantic partner Lance Twiggs, is shown during a preliminary hearing in court
‘[Redacting the video] suggests to the public that something else is in there, that something else lurks in there that isn’t,’ her attorney, Jeffrey Neiman, argued.
Judge Tony Graf ultimately permitted a partially redacted version of the interview to be played publicly.
Graf is expected to decide after further arguments on September 1 whether prosecutors have presented sufficient evidence to send Robinson to trial.
Kirk, a close ally of President Donald Trump and founder of Turning Point USA, was 31 when he was shot once in the neck while taking questions from thousands gathered at Utah Valley University.
Robinson has not entered a plea, and his attorneys have not publicly commented on his guilt or innocence.
They have, however, challenged key pieces of the prosecution’s forensic evidence and unsuccessfully sought to remove the death penalty from the case.