Mantell, Green Fireballs, Nuclear Facilities, and 19 New Infrared Videos
The fourth PURSUE tranche, published July 10, 2026 through the Pentagon's official disclosure portal, released 40 files spanning incidents from 1948 through 2025. The package — comprising 14 documents, 19 infrared videos, 4 audio recordings, and 3 images — includes some of the oldest officially acknowledged UAP records ever released to the public, alongside contemporary military footage that has never previously been seen outside classified channels.
KEY FINDINGS
THE 1948 MANTELL INCIDENT — NEWLY DECLASSIFIED DOCUMENTS
Among the most historically significant releases in the fourth tranche are newly declassified documents revisiting the fatal 1948 pursuit by National Guard pilot Captain Thomas Mantell. On January 7, 1948, Mantell's aircraft crashed after he pursued an unidentified object over Kentucky. According to newly released records, his last radio transmission described a large metallic object of tremendous size moving at considerable speed. The documents reveal that investigators at the time could not attribute the object to any known aircraft, balloon program, or natural phenomenon. Project Sign — the forerunner to Project Blue Book — classified the case and the full investigative record was not previously available. The incident is notable not only for its tragic outcome but for being one of the earliest cases in which an object described as structured and metallic was observed by multiple trained military personnel.
1949 LOS ALAMOS "GREEN FIREBALLS" — SCIENTIFIC CONFERENCE TRANSCRIPTS
The fourth release includes transcripts from a 1949 scientific conference convened to assess unexplained green fireballs repeatedly observed over the Los Alamos National Laboratory nuclear complex in New Mexico. The documents show that leading scientists of the period — including researchers from Los Alamos itself — could not reach consensus on whether the objects were meteors, atmospheric phenomena, or something else entirely. Conventional meteor explanations were debated at length but did not satisfy all participants, particularly given the objects' reported trajectories, brightness, and frequency of occurrence near a sensitive nuclear installation. The transcripts represent the earliest known formal scientific discussion of UAP over a U.S. nuclear facility that has been made publicly available.
2015 PANTEX NUCLEAR WEAPONS COMPLEX — SURVEILLANCE AND LOCKDOWN
One of the most operationally significant cases in the fourth release involves the Pantex Plant in Amarillo, Texas — the United States' primary nuclear weapons assembly and disassembly facility. According to released security records, personnel observed an unidentified object over the complex in 2015, prompting a facility lockdown. Surveillance imagery was captured and subsequently enhanced by Sandia National Laboratories. All evidence was forwarded to the FBI. The documentation confirms that the incident was treated as a serious security matter at the highest level of the nuclear complex hierarchy. Investigators assessed multiple explanations — commercial drones were not yet common in the area — and could not definitively attribute the object to any known platform. The case represents the most recent confirmed UAP incident over a U.S. nuclear weapons production facility to enter the public record.
2019 MILITARY TRAINING ENCOUNTER — AVIATOR TESTIMONY
A Navy and USAF aviator with nearly three decades of service filed a formal report describing an object observed during military training operations in 2019 with flight characteristics unlike anything encountered during their career. The report was filed through standard Range Fouler reporting procedures — the military protocol for documenting unidentified objects entering restricted airspace during exercises. The aviator's account describes an object that exhibited no visible propulsion, made no detectable sound, and maneuvered in ways inconsistent with any known aircraft or drone. The formal use of Range Fouler procedures rather than informal reporting is significant: it means the encounter was treated as a real and immediate airspace concern at the time rather than a post-flight observation.
NINETEEN INFRARED VIDEOS — MILITARY SENSOR FOOTAGE
The largest single category of material in the fourth release is a set of nineteen previously classified infrared videos captured by military sensors during separate incidents across multiple years. The videos were recorded by airborne platforms using thermal imaging equipment. Objects depicted vary in shape, behavior, and apparent size across the footage. None has been officially attributed to foreign aircraft, commercial drones, known atmospheric phenomena, or sensor artifacts with high confidence. Officials emphasized that no video in the release constitutes confirmation of extraterrestrial origin. The nineteen videos represent the largest single batch of military UAP footage released to the public in U.S. history.
RELEASE COMPOSITION
The fourth tranche consists of 40 files total: 14 documents, 19 videos, 4 audio recordings, and 3 images. Source agencies include the Department of Defense, FBI, CIA, NASA, and the Department of Energy. The inclusion of Department of Energy records — covering incidents at nuclear facilities — is new to the PURSUE release series and reflects expanding scope across the national security apparatus. Material in the release spans incidents from 1948 through 2025, making it the most historically broad tranche released to date.
14
Documents
19
Videos
4
Audio
3
Images
WHAT STOOD OUT
The fourth release is distinguished by two qualities absent from previous tranches: its historical reach and its nuclear context. Prior releases focused primarily on post-2000 cases. The fourth tranche extends the official UAP record back to 1948 and places several of the most notable cases directly adjacent to nuclear installations — Los Alamos in 1949, Pantex in 2015. Whether this proximity is meaningful or coincidental is a question investigators have not answered. The release also marks the first time formal scientific transcripts from a government-convened UAP discussion have been made publicly available, providing a rare window into how the scientific establishment engaged with the subject during the early Cold War.
OVERALL ASSESSMENT
The fourth PURSUE release extends the established pattern of the series: substantive historical and contemporary material is released, multiple cases remain unresolved, and no release confirms extraterrestrial origin for any incident.
- —The historical scope of the fourth tranche — spanning 1948 to 2025 — demonstrates that the UAP archive extends far deeper into American military and scientific history than previous public acknowledgments suggested.
- —The concentration of cases near nuclear installations across multiple decades raises questions that investigators have noted but not answered regarding whether UAP activity shows any meaningful correlation with nuclear infrastructure.
- —The nineteen infrared videos constitute the largest single batch of classified military UAP footage ever released to the public, setting a new baseline for what the government has been observing and recording.
As with previous releases, the value of this tranche is not in definitive answers but in the breadth of the record now available for independent review. Researchers, historians, and the public can now examine the same documentation that government investigators have held for decades.
None of the documents, videos, audio recordings, or images in the fourth PURSUE release confirm extraterrestrial origin, recovered non-human technology, or verified non-human intelligence. All cases with unresolved explanations remain open investigations.