Operation Belttrap was an attempt to capture the alien and its craft after it had been found by the Soviets in the 1950s. The operation was conducted under the cover of Operation Argus that were a series of nuclear weapons and missiles test during August and September 1958.
The United States Navy Task Force 88 found the crashed space craft and took it to their containment facility at Area 51 to be examine it. They also managed to capture the alien, and "recreate" its probable environment in a massive cave-like cage. The scientists concluded that the creature was subterranean from looking at some of its anatomical features. The scientists fed it large quantities of meat. However, this led to one of the scientists being attacked and the creature escaping.
Operation Belttrap continued with the Alien being transported by the United States Air Force to a secret facility in Ohio, most likely Write-Patterson Air Force Base. However it was interrupted by Thomas Woodward, who rammed his car directly into the train, causing it to derail with a massive crashes and explosions and the alien escaping to the nearby town of Lillian, Ohio.