Since the war that toppled Col. Muammar el-Qaddafi began in 2011, arms-tracking analysts have warned that weapons looted from the colonel's stockpiles could find their way to militants in sub-Saharan Africa.
Although public evidence for transfers has been scarce or not fully verifiable, persistent accounts of smuggled arms reaching Mali have circulated for more than a year, just as reports have repeatedly suggested that weapons formerly in Libya were turning up in Egypt, Gaza, Chad, Lebanon, Syria and elsewhere.
In the case of Mali, the reports appeared alongside signs of the growing strength of jihadists in the country's north. The timing, researchers said, suggested that weapons from Libya had changed the course of Mali's war -- so much so that the French military eventually intervened.
Recent photographs from Mali provide perhaps the clearest publicly available indication yet that these transfers have in fact occurred.
The first photograph, filed on Jan. 26 by Reuters, shows a slightly damaged finned projectile resting on the dirt in Konna, the city in central Mali from which a French-led military attack expelled militants last month. A New York Times photographer later documented more examples of the same weapons.
The projectiles in question were NR-160s, antitank munitions manufactured by a now-defunct company in Belgium that in the 1970s and 1980s extensively sold arms to Colonel Qaddafi's military. Fired through American-designed recoilless rifles that have a history in Libya since early in the cold war, the projectiles were identical to ordnance documented in Libya in 2011.
They had been left behind in Konna by Islamists who had been pounded by an aerial attack, and suffered many losses.
Many other types of weapons that could have come from Libya have been present in the fighting in Mali, including Soviet-era assault rifles, machine guns and rocket-propelled grenades. Unlike these items, the NR-160 was not a widely distributed or globally produced export product that could have come from myriad sources. It was a peculiar item with a limited circulation and a well-established tie to Libya.
When combined with images of other weapons strongly associated with Libya that have also turned up in Mali, the presence of NR-160s suggests that evidence is hardening that weapons cast loose in Libya are contributing to instability elsewhere, perhaps most vividly in Mali.
It also offers insight into arms deals that have gone awry, and foreign policy choices that had costly, unintended effects.
"What was incredible in Libya was how much was there, and the things that turned up that haven't been seen anywhere else," said Neil Corney of the Omega Research Foundation, which examines the manufacture and circulation of military and police equipment.
Of the likely effects of Libyan weapons on Mali, he said, "There was a sudden push by better armed, better equipped and better organized forces in Mali that pushed Mali's army out."
"The timing," he said, "was right."
According to the conventional wisdom of governments and arms manufacturers, well-coordinated arms exports can help strengthen vulnerable states, professionalize military forces and promote stability.
In Libya, the opposite occurred, and the related dangers radiated outward.
This presumed influx of weapons to Mali from Libya has in turn underscored the unwanted effects of a war supported by the West, and raised questions anew about why NATO and the allied militaries that helped defeat the Qaddafi military did little to contain weapons that foreign military intervention helped set loose.
In the case of the NR-160s, several strands of evidence point to Libya as the source.
A projectile with an armor-penetrating shaped charge, the NR-160 was one of several rounds in the 106-millimeter class produced by Poudreries Réunies de Belgique, a Belgian company that sold ordnance to Libya in the early Qaddafi era.
These rounds were manufactured for M40 recoilless rifles, which were designed in the United States in the 1950s.
As part of efforts to prop up King Idris of Libya and retain access to an air base near Tripoli, the State Department and the Pentagon helped create and equip Libya's army in the 1950s and 1960s. The engagement included providing the nascent army with recoilless rifles.
By 1969, Washington's ambition had backfired. Rather than protect the monarchy, the army nurtured by the United States had produced Colonel Qaddafi, who overthrew the throne and forced the United States to abandon the base.
After the coup, as Colonel Qaddafi sought new sources for weapons, the Belgian company helped satisfy Libya's procurement desires. It sold Libya many classes of ordnance, including land mines and antitank projectiles.
Research in Belgium's state archives by Damien Spleeters, an independent arms researcher, found that from 1973 to 1980, the company received multiple licenses to ship 106-millimeter recoilless rifle rounds to the "Directorate Military -- Tripoli, Libya."
Mr. Spleeters's searches of public records found no evidence of other transfers of 106-millimeter rounds to any other country in the region, with the exception of a 1971 license approving a tiny shipment -- 200 rounds -- to Morocco. One license alone for shipments of 106-millimeter rounds to Libya, by contrast, authorized the transfer of 30,000 rounds.
For decades these arms were locked up within Colonel Qaddafi's secretive state, their quantities unknown. The Belgian company's 106-millimeter rounds resurfaced spectacularly in 2011, used by both Qaddafi loyalists and rebels who seized them from captured government stockpiles.
The M40 ultimately proved to be one of the most effective weapons that the rebels acquired, and it was repeatedly used to breach buildings where pro-Qaddafi soldiers had hidden.
As the war ran its course, Belgian 106-millimeter rounds and their associated wooden crates were photographed several times by The Times, by rebel logisticians and later by bomb disposal technicians.
The projectiles found in Mali, whose army, according to the International Institute for Strategic Studies, does not possess M40 recoilless rifles, match these records. One arms-trafficking researcher who has examined the stocks of many African states said the photographs of the projectiles in Konna documented a weapon that had no likely regional source other than Libya.
"From what I have seen in the sort of fossil record in situ in armories of Western African states, you don't find this particular weapon," said James Bevan, director of Conflict Armament Research, a private arms-tracking company in Britain. "We would have seen them. And we haven't."
This article originally appeared in The New York Times.