The Gulf Mystery Deepens: Witness Accounts, a Misplaced Seismograph, and the Evolving Investigation into the Disappearance of Randall Spivey and Brandon Billmaier

As the calendar turned to the final days of 2025, the disappearance of Florida attorneys Randall Spivey and Brandon Billmaier continued to captivate public attention and fuel speculation far beyond Southwest Florida. The 42-foot Freeman catamaran Unstopp-A-Bull, found adrift and unmanned on December 20 approximately 70 miles west of Fort Myers, remained the central artifact in an investigation that has now entered its second week without resolution. The FBI’s lead role, combined with renewed public interest, has prompted the release of additional investigative details—some of which have dramatically shifted the prevailing theories.

The Witness Who Saw Them Last

On the afternoon of December 23, the Lee County Sheriff’s Office (LCSO) and federal investigators publicly acknowledged a previously unreported witness statement that had been received early in the search. A commercial fisherman operating a 28-foot center-console vessel approximately 12–15 miles northeast of the Unstopp-A-Bull’s eventual discovery location contacted authorities on the morning of December 20. The fisherman, whose identity has been withheld pending formal interview, claimed to have observed the Freeman catamaran under way at roughly 11:30 a.m. on December 19.

According to the witness, he was trolling for kingfish when he noticed the larger vessel approaching at speed from the south-southeast. He estimated the distance at 300–400 yards. Through binoculars, he observed two figures on the aft deck near the transom—one wearing a blue-and-yellow auto-inflating life vest. The witness stated that both men appeared to be “leaning over the side,” possibly handling something in the water. Moments later, the catamaran veered slightly to starboard and continued on its course, engines still audible. When the fisherman later checked the same area, the boat was gone, and he saw no signs of the two individuals.

The account was initially treated as one of many tips flooding in during the search. However, after the Unstopp-A-Bull was recovered and its position data analyzed, investigators determined that the witness’s reported sighting aligned almost exactly with the catamaran’s last known GPS track at approximately 11:28–11:32 a.m. on December 19. The vessel’s onboard GPS chart plotter showed a steady course of 290 degrees (west-northwest) at 38 knots, consistent with the fisherman’s description.

Review of Remaining Equipment and the Discovery of the Anomalous Device

When the Unstopp-A-Bull was towed to Fort Myers Beach and secured for forensic examination, investigators cataloged every item aboard. The inventory included:

Multiple high-end fishing rods and reels (none in the water)

Tackle boxes and lures
A partially filled insulated fish box containing several mahi-mahi
Two cell phones, wallets, keys, and personal items belonging to both men
One blue-and-yellow auto-inflating life vest still clipped to the console
One white throwable life ring
The unused EPIRB still mounted in its bracket
A small sealed cooler containing bottled water, energy drinks, and a single sealed plastic bag

Inside that bag, secured with a tamper-evident zip tie, was a compact digital seismograph—a device roughly the size of a small toolbox, weighing approximately 12 pounds, and bearing a manufacturer label identifying it as a RefTek 130-REN portable broadband seismometer. The device was not listed on any of Spivey’s or Billmaier’s known equipment inventories, nor had either man ever been documented as having an interest in geophysics or seismology.

The presence of the seismograph immediately changed the investigative focus. A preliminary review of the device’s internal memory card revealed that it had been actively recording data from approximately 09:15 a.m. until 11:34 a.m. on December 19. The last recorded timestamp occurred just two minutes after the witness’s reported sighting of the two men near the transom. The seismograph’s final data burst showed an anomalous low-frequency vibration spike—described by preliminary analysis as “consistent with a localized underwater disturbance of significant energy.”

Shift in Hypothesis: From Accident to Possible External Event

The discovery of the seismograph and its recorded data prompted investigators to reclassify the case from a presumed boating accident or man-overboard incident to one requiring a broader examination of possible external factors. Several new hypotheses have emerged, though all remain under active investigation and none have been officially confirmed:

Underwater Explosion or Pressure Wave The seismograph’s final data spike could indicate a subsurface event—such as a small detonation, gas pocket release, or even a large marine animal striking the hull. The sudden nature of the men’s disappearance, combined with the vessel continuing under power, supports the possibility that both individuals were incapacitated or ejected by a rapid, violent event.
Unreported Scientific or Research Activity Though neither Spivey nor Billmaier had any known background in geophysics, the presence of a high-quality seismograph suggests the possibility that the men were assisting someone else with a research project. Speculation has circulated on boating forums that they may have been asked to deploy or retrieve the device in a remote area of the Gulf, potentially for a university, private company, or government entity. No such arrangement has been publicly confirmed.
Intentional Placement and Disappearance A minority view posits that the seismograph was deliberately placed aboard as part of a larger plan. Some online commentators have suggested the device could have been used to mask or monitor an intentional exit from the vessel—though this theory lacks supporting evidence and contradicts the families’ statements that both men were safety-conscious and deeply family-oriented.

The FBI has reportedly contacted several academic institutions and private geophysical companies operating in the Gulf region to determine whether the seismograph matches any equipment reported missing or loaned out in recent months. Additionally, the Coast Guard’s navigation team is re-examining AIS and radar tracks from other vessels in the area during the critical time window to identify any vessels that may have been near the Unstopp-A-Bull at the moment of the anomaly.

Public Reaction and Ongoing Search

The revelation of the seismograph and the witness account have reignited hope among some family members and supporters. Deborah Billmaier posted on social media: “We now know someone saw them alive and well just minutes before. That gives us strength to keep going.” Tricia Spivey has remained largely silent but is said to be cooperating fully with federal investigators.

Private search efforts continue, with several volunteer vessels still combing the Gulf for any signs of debris or personal effects. The families have also hired a private marine salvage firm to assist in mapping potential drift paths from the last known position.

A Case That Defies Simple Explanation

As of December 30, 2025, the disappearance of Randall Spivey and Brandon Billmaier remains officially unresolved. The discovery of a single, misplaced seismograph has transformed what many initially viewed as a tragic but straightforward boating accident into a complex mystery with scientific, maritime, and potentially criminal dimensions.

Investigators continue to urge anyone with information—particularly regarding the origin or purpose of the seismograph—to contact the FBI tip line or LCSO directly. In the absence of definitive answers, the Unstopp-A-Bull sits quietly at the dock in Fort Myers Beach, a silent witness to an event that may have been far stranger and far more deliberate than anyone initially imagined.