Charlie Kirk Shooting Criminal Hunt included hints of unusual forensic techniques

The suspect was identified as Tyler Robinson on Friday as a search for the assassin of conservative political activist Charlie Kirk unfolded, and law enforcement analyzed every lead. One proof they returned home: printing of forearms taken from the sniper’s position.

Before Robinson’s arrest Friday morning, as a result of Robinson’s highly human methods, Robinson offered his family what could be a form of confession, and then shared the information, FBI agent Robert Balls said investigators had collected “impressions of footwear, printed palms, and stamps from crime scenes for analysis.”

Experts spoken by CNBC say forearm imprinting is not generally collected evidence.

“That’s very unusual,” said Patrick McClain, a Texas-based criminal defense lawyer and retired Marine military judge. McClain explained that when forearm printing is usually mentioned, authorities collected DNA or other skin residues from the surface on which the forearm was pressed.

“We’ve seen a lot of people in the world,” said Jeff Weining, founder and CEO of Law Enforcement Consultants, who have worked with the LAPD Elite Metropolitan Division and the Secrets Bureau that protects senior officials. “It would look like a mold-lifted shoe or a boot print,” he added.

Forearm printing can be used to support identification purposes, including unique properties such as scarring and traces of wear on known clothing.

“Like fingerprints, forearm printing can be unique enough to identify if there is sufficient quality,” he said.

Additionally, if biological materials such as sweat, body oils and touch DNA can be recovered, it may have forensic value if it, along with other evidence, can support or contradict witness statements and video footage.

New technology is giving the forearm a wider window to potential suspects. Physical impressions have been used in forensic research for many years, but in recent years, methodologies for identifying and comparing specific meaningful markings have evolved, and scanning technology for analyzing imprints “feels new.”

3D scanning revolutionized this science, turning the forearm prints into previously undeveloped information reservoirs. Imprinting alone cannot determine factors such as ethnicity or gender. Investigators also rely on whether DNA or other biological evidence was obtained from the traces.

“It’s a new exploration of forensic medicine that includes other skinprints, but it’s not something like a 100% unique finger/palm print,” said Toby Braun, CEO and founder of the American Special Investigative Group, which specializes in executive protection, threat intelligence monitoring and complex investigations.

According to Braun, forearm printing does not identify people from the database like fingerprints. “Forearm printing is not considered a major form of forensic evidence, just like fingerprints,” he said.

According to Braun, forearm printing is not a major form of evidence, as it may be ambiguous. For example, the friction ridges of the fingers and palms are unique to each individual, but the skin on the forearm does not have the same detailed, permanent, individualized ridge pattern.

The difficulty with forearm residues is that even in the most popular cases, DNA takes time to get results and is not beneficial until there is an arrest if the person is not included in a known database. “There wouldn’t have been too many people on the roof of the building,” McClain said. “But it’s not like a fingerprint. There’s no unique structure on every person’s forearm.”

According to McClain, if there were anything unique, such as tattoos or scar patterns, there were cases where they were tested with forearm prints.

Like other Manhunts, the focus was on finding and arresting a shooter in the hours after filming. “As the investigation is still ongoing, additional evidence of the most powerful case will be developed,” Brown said, adding that authorities need a possible cause of arrest and that evidence beyond reasonable doubt is for trial. “But it was developed as the case progressed,” he added.

Dan Gel, founder and administrator of the following law, states that in order to lift or photograph the forearm “patterns” the subjects must apply sufficient pressure on the receptive surface area, and that the print is most useful as support evidence rather than primary, as supportive evidence, as a search warrant for additional evidence.

“In certain circumstances, forearm printing may be acceptable in courts. Like all scientific evidence, forearm printing must be recognized by the testimony of a qualified expert and pass the court’s reliability test,” Gerl said. This type of forensic evidence is likely to clear more procedural hurdles before it is granted in court, he added.

Robinson was arrested on suspicion of aggravated murder, felony discharge from the firearms and obstructing justice by police. The prosecutor ultimately decides the charges he will face in court. This is scheduled to be submitted on Tuesday.

Ultimately, Tyler Robinson’s arrest came down to humans rather than forensic connections. And some crime experts say that the critical feature of recent political violence is the murderer’s fundamental desire to be captured rather than carefully planned and avoided capture.

Brina Fox, a former FBI special agent and professor of criminology at the University of South Florida, says advances in criminal technology have been notable over the past two years, with some offenders likely noticing the level of forensic medicine available to law enforcement. “He might have been thinking, ‘Yeah, I can leave a print on my forearm and that’s nothing,” Fox said.

But she believes that a different way of thinking could have been at work. When comparing the Robinson case to the case of Luigi Mangion, who assassinated a unified medical executive last year, Fox believes ideologically driven criminals are more interested in sending messages than avoiding the outcome of their crimes.

In other words, they may not be thinking of any traces of evidence that are as lingering as other criminals. Printed material, face covering, weapons being disposed of, etc. “Attention helps to give you more oxygen to what the ideologue wants to say,” Fox said. “In a sense, there’s a certain provision in the fact that they’re okay with being arrested and leaving some evidence behind. They don’t want to catch them right away, but their main mission is to achieve their goals.