The night an Air Force jet mysteriously disappeared over Lake Superior—November 23, 1953—was a stormy one.

Near the U.S.-Canadian border, U.S. Air Defense Command noticed a blip on the radar where it shouldn’t have been: an unidentified object in restricted air space over Lake Superior, not far from Soo Locks, the Great Lakes’ most vital commercial gateway. An F-89C Scorpion jet, from Truax Air Force Base in Madison, Wisconsin, took off from nearby Kinross AFB to investigate, with two crew members on board. First Lieutenant Felix Moncla—who had clocked 811 flying hours, including 121 in a similar aircraft—took the pilot’s seat, while Second Lieutenant Robert Wilson was observing radar.

The men would not return from their intercept mission.

What followed, according to Donald Keyhoe, the former Marine Corps naval aviator and UFO researcher who wrote about the incident in his 1955 book The Flying Saucer Conspiracy—was “one of the strangest cases on record.”

Once airborne, Lieutenant Wilson had difficulty tracking the unknown object, which kept changing course. So with ground control directing the aviators over the radio, the Scorpion gave chase. The jet, traveling at 500 miles per hour, pursued the object for 30 minutes, gradually closing in.

On the ground, the radar operator guided the jet down from 25,000 to 7,000 feet, watching one blip chase the other across the radar screen. Gradually, the jet caught up to the unknown object about 70 miles off Keweenaw Point in upper Michigan, at an altitude of 8,000 feet, approximately 160 miles northwest of Soo Locks.

At that point, the two radar blips converged into one—“locked together,” as Keyhoe would put it later. And then, according to an official accident report, the radar return from the F-89 simply “disappeared from the GCI [ground-controlled interception] station’s radar scope.”

And then the first radar return, indicating the unidentified object, veered off and vanished too.

The United States Air Force, United States Coast Guard and Canadian Air Force conducted an extensive search-and-rescue effort. No wreckage, or sign of the pilots, was ever found.

The Air Force’s official news release about the disappearance, delivered to the Associated Press, stated that the vanished jet “was followed by radar until it merged with an object 70 miles off Keweenaw Point in upper Michigan.” The statement appeared in a story in the Chicago Tribune with the headline, “JET, TWO ABOARD, VANISHES OVER LAKE SUPERIOR.”

The Air Force soon retracted the statement and changed its story: According to the new statement, the ground control radar operator had misread the scope. In fact, the F-89 had successfully completed the mission, intercepting and identifying the UFO as a Dakota—a Royal Canadian Air Force C-47 aircraft—flying some 30 miles off course. Lieutenant Moncla, probably stricken with vertigo, crashed into the lake during the return to base. Canadian officials refuted the account—no flights had taken place in the area that night.

According to Keyhoe, who would write about the Kinross Incident again in his 1973 book Aliens From Space, two separate Air Force representatives provided Lieutenant Moncla’s widow with contradictory explanations of the incident. In one version of events, the pilot had crashed into the lake while flying too low. In the other, the jet exploded at a high altitude.

The case file from Project Blue Book, the Air Force’s own UFO investigatory team, reiterated the Air Force assertion that the jet “successfully accomplished its mission,” and that the crash was an accident, “probably” caused by an “attack of vertigo.” It attributed the abnormal radar behavior to unusual “atmospheric conditions” and deemed the inability to recover wreckage as understandable, given the deep water.

Meanwhile, investigators from the National Investigations Committee on Aerial Phenomena (NICAP) discovered that any mention of the mission had been expunged from official records. And the Aerospace Technical Intelligence Center’s official line on the case was: “There is no record in the Air Force files of sighting at Kinross AFB on 23 November 1953… There is no case in the files which even closely parallels these circumstances.”

In the absence of a thorough and satisfying official explanation, “civilian saucer groups,” as Project Blue Book would call them, developed their own theories. According to one, the jet had crashed into the UFO’s protective beam like a “concrete wall.” Others speculated that the jet may have been “scooped” out of the air and taken aboard the spacecraft—perhaps so the captured men could teach their alien captors the English language.

In 1968, there were local newspaper reports of military jet fragments discovered near the shore of Lake Superior, but the find was never verified.

In 2006, Adam Jiminez, claiming to be a representative of the Great Lakes Dive Company, corresponded with UFO bloggers and members of the UFO community. He claimed that not only had an airplane wreck been discovered in the area, but a metallic object resembling a chunk of a flying saucer as well.

UFO researchers soon exposed inaccuracies in Jimenez’s story, and concluded that the Great Lakes Dive Company did not exist. Eventually, Adam Jimenez, too, vanished without a trace.