WASHINGTON - In passing references scattered through once-classified documents and cryptic public comments by former intelligence officials, it is referred to as "Midwest Depot," but the bland code name belies the role it has played in some of the CIA's most storied operations.

From the facility, located somewhere in the United States, the CIA has stockpiled and distributed untraceable weapons linked to preparations for the Bay of Pigs invasion and the arming of rebels and resistance fighters from Angola to Nicaragua to Afghanistan.

Yet despite hints that "Midwest" was not actually where it was located, the secrecy surrounding the CIA armory has survived generations of investigations. In a 2007 essay on the 20th anniversary of the Iran-contra affair, for example, a congressional investigator noted that the facility where the CIA had handled missiles bound for Iran remained classified even as other "incredible things were unveiled during the hearings."

But three years ago, it became public that the CIA had some kind of secret location at Camp Stanley, an Army weapons depot just north of San Antonio and the former Kelly Air Force Base, though its purpose was unclear. And now, a retired CIA analyst Allen Thomson has assembled a mosaic of documentation suggesting that it is most likely the home of Midwest Depot.

In December, he quietly posted his research, which he has updated several times with additional clues, on the website of the Federation of American Scientists. In an email exchange, Thomson argued that the Midwest Depot's history should be scrutinized.

"I have worried about the extent to which the U.S. has spread small arms around over the decades to various parties it supported," he said. "Such weapons are pretty durable and, after the cause du jour passed, where did they go? To be a little dramatic about it, how many of those AK-47s and RPG-7s we see Islamists waving around today passed through the Midwest Depot on their way to freedom fighters in past decades?"

Spokesmen for the Pentagon and the CIA declined to comment. A public affairs officer for Camp Stanley said its mission was to be a weapons storage and testing facility for the military.

There is no outward indication of what would be one of the CIA's three known facilities in the United States, along with its headquarters in Langley, Va., and Camp Peary, a military base near Williamsburg, Va., known by its code name, "The Farm," that is believed to be used for training. Camp Stanley has a low-key gated entrance, and a few nondescript warehouses are visible from its fence. Rows of bunkers are nestled deeper into the base, according to satellite images.

The mayor of the nearby town of Boerne, Mike Schultz, said he knew nothing of any CIA presence at Camp Stanley. Henry Cisneros, a former mayor of San Antonio who served as secretary of Housing and Urban Development, also said he had never heard speculation about a CIA role there.

Several of the documents Thomson found traced Midwest Depot's role without identifying its location, including a 1967 CIA memo linking it to paramilitary training of Cuban exiles before the 1961 Bay of Pigs invasion, and a 1987 State Department memo showing that equipment bound for the Nicaraguan contras passed through it.

Thomson found an explicit reference in a 1986 memo by Col. Oliver North, a chief figure in the Iran-contra affair. It said the CIA would truck missiles bound for Iran from a military arsenal "to Midwest Depot, Texas" for preparation, then fly them out of Kelly Air Force Base. Connecting Midwest Depot to yet another historical episode, it added that some missiles would go to "Afghan resistance" fighters battling the Soviets.

Just last July, according to another document Thomson spotted, the Army sought to purchase 2 million rounds of ammunition of the caliber that fits AK-47 rifles, which U.S. soldiers do not use. The delivery address: Camp Stanley.