Pentagon Reveals New Details on Mysterious “Prominent Hunt” Exercise to “Find Nuclear Event Perpetrators”

Micah Hanks·
nuclear incident
(Credit: Master Sgt. Mark Olsen/U.S. National Guard)

Welcome to this week’s installment of The Intelligence Brief… recently, the U.S. Department of Defense issued an update on a series of training exercises to enhance capabilities for finding the perpetrators in the aftermath of a nuclear attack. In our analysis, we’ll be looking at 1) the joint DoD-FBI training exercise federal authorities carried out in New York earlier this year, 2) new details the DoD has provided on the “Prominent Hunt” exercise, 3) how it aims to be more than just a detection capability, but also a deterrent against future attacks, and 4) how future training in the months ahead will add to the U.S.’s defense capabilities against possible nuclear threats.

Quote of the Week

“We’re looking for those radiological fingerprints, those things that are unique to different countries, to be able to point back to where the nuclear weapon came from.”

 – Timothy Jacomb-Hood, Senior Science Adviser, Office of Nuclear Matters

RECENT NEWS from The Debrief

U.S. Strengthens Ability to “Find Nuclear Event Perpetrators”

On Wednesday, the U.S. Department of Defense (DoD) provided an update on a large-scale nuclear incident training exercise conducted in New York earlier this year.

The exercise, known as Prominent Hunt, led to speculation earlier this year following the publication of a news release by the Federal Bureau of Investigation (FBI), which participated in the training operation alongside several other agencies.

Characterized as “a large-scale, multi-agency nuclear incident training exercise,” the operation occurred around Schenectady, New York, between January 26-31, 2025. Officials said that New York residents should not be alarmed at the time, as the exercise would “not pose any risk” due to “training-related activity, including the presence of military personnel and aircraft, and people in protective equipment.”

Prominent Hunt

The recent iteration of Prominent Hunt was a large-scale nuclear forensics exercise designed to test the U.S.’s ability to collect and analyze evidence after a nuclear detonation. The operation, led by the FBI and the DoD, primarily focused on developing the U.S.’s ability to rapidly identify the source of a nuclear attack and provide crucial intelligence for national decision-making.

Prominent Hunt is part of an ongoing interagency effort to refine nuclear forensic techniques, with similar training exercises carried out by the FBI and DoD in partnership with other federal agencies in the past. Other participants in January’s round of exercises saw participation from the Department of Energy’s National Nuclear Security Administration (NNSA), the Army’s 20th CBRNE Command, and the Air Force Technical Application Center.

All these agencies contribute to the National Technical Nuclear Forensics Ground Collection Task Force, an interagency group primarily responsible for collecting debris samples from any potential nuclear detonation site. Samples retrieved by participating agencies are transported to DoD labs for analysis, which is a crucial step in determining the origins of any potential nuclear attack.

Determining the Source of a Nuclear Detonation

Should such a nuclear incident ever occur, forensic analysis will play a critical role in identifying the origin of any such weaponry used.

For instance, unique radiological “fingerprints” left behind from the use of elements like uranium or plutonium can reveal details like the country that produced the material, which grants intelligence officials key insights into questions like whether a state actor, a terrorist group, or some other entity carried out the attack.

Beyond simply identifying the possible perpetrators in the aftermath of a nuclear attack, the DoD said on Wednesday that U.S. agencies publicly demonstrating such forensic capabilities serves as a deterrent to any would-be adversaries planning such attacks.

“National technical nuclear forensics is absolutely a part of nuclear deterrence by messaging to our adversaries that the United States government has the capability, should there be a nuclear detonation,” said Brian Kohler, director of Nuclear Forensics, Energy, and Survivability at the DOD’s Office of Nuclear Matters, in a statement this week, emphasizing that adversaries must recognize that no nuclear attack will go untraceable.

“These technical skills and tools deny potential perpetrators—including state sponsors of terrorism—anonymity and ensure they will be held fully accountable,” added Wendin Smith, the NNSA’s associate administrator and deputy undersecretary for counterterrorism and counterproliferation.

Preparing for “Alternative Threats”

Although nuclear attacks are often associated with missile strikes or explosives used by hostile nations, Prominent Hunt’s main focus involved “alternative” threats that include those posed by terrorist organizations or rogue states, which are more likely to rely on using improvised nuclear devices.

Improvised devices are more likely to be used by such groups since their components can more easily be smuggled into a major population area rather than requiring a launch mechanism. In addition to making the devices less easily detectable before their use, the DoD emphasized on Wednesday that their origins are also less easily traced to any specific nation.

Given the challenges such devices present to U.S. agencies, forensic evidence becomes crucial in helping determine where any such weapon may have come from and how perpetrators got it there. At the heart of this effort is the requirement for collecting on-the-ground data from the detonation site, without which intelligence agencies would face the difficult task of attempting to trace the origins of nuclear devices back to their originators.

Exercises undertaken during Prominent Hunt included training forensic teams to work rapidly to collect radioactive debris from an affected area using models that help predict where debris is likely to fall. This incorporates weather data, as well as explosion yield based on the device’s size and surrounding area and the estimated altitude of the explosion.

These models, developed by teams at the Air Force Technical Applications Center, help forensic scientists pinpoint the best collection sites, directing teams from the 20th CBRNE Command to retrieve diverse samples for laboratory analysis. Additional evidence may be gathered in the form of airborne debris. At the same time, satellite surveillance capabilities can also be leveraged to help track where materials may be found in the aftermath of a nuclear attack.

Validating Readiness Through Repeated Exercises

The DoD is expected to publish an after-action review of January’s training operation in the weeks ahead. Meanwhile, a second series of training exercises under Prominent Hunt has already been scheduled for later in 2025, and the DoD expects it to take place in August.

Additionally, the Defense Threat Reduction Agency (DTRA) will participate in planning the exercises, allowing the Office of Nuclear Matters to focus more on oversight and guidance.

Drew Walter, deputy assistant secretary of defense for nuclear matters, said that the recent Prominent Hunt exercise successfully validated the task force’s ability to collect and analyze nuclear debris.

“Our DOD team demonstrated their readiness to collect forensics-quality debris samples, working with their FBI and NNSA partners,” Walter said this week.

“Our ability to gather post-detonation debris and perform nuclear forensics analysis is a key element of our nuclear deterrent,” he added.

That concludes this week’s installment of The Intelligence Brief. You can read past editions of our newsletter at our website, or if you found this installment online, don’t forget to subscribe and get future email editions from us here. Also, if you have a tip or other information you’d like to send along directly to me, you can email me at micah [@] thedebrief [dot] org, or reach me on X: @MicahHanks.

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