The plane was feared to be in the hands of international terrorists. It was spotted late last month in Conakry, Guinea’s capital, by Bob Strother, a Canadian pilot.
It had been re-sprayed and given the Guinean registration, 3XGOM. But, at least the last two letters of its former tail-number, N844AA, were still visible.
The plane was being used to shuttle goods between Beirut and Conakry, according to Mr Strother.
"There’s no absolutely doubt it’s the same aircraft. The old registration is clearly visible," said Mr Strother.
"Whoever owns it must have some important friends, to get it re-registered in two days - going by the book, the whole process usually takes a couple of months."
Western intelligence agencies were said to be scouring Africa’s skies and runways for the missing plane, egged on by fears that it could easily be aimed at an American or British embassy in Africa.
One US official said this was the first he had heard of the plane since its disappearance from Angola’s capital of Luanda on 25 May.
"People have been looking for this thing everywhere," the official said.
"We’ve had reports that it crashed, that it was in South Africa or Nigeria, but nothing for sure, not like what you’ve just told me."
Immediately after its disappearance, American intelligence operators said "the plane mostly likely was taken for a criminal endeavour such as drugs or weapons smuggling". But, they did not rule out the possibility it was stolen for use in a terrorist attack and were making every effort to get to the bottom of the mystery.
A Western diplomat in Freetown, Sierra Leone’s capital, said it was more likely the plane had simply been snatched from Luanda because its owner was reluctant to pay year-long airport taxes, totalling $50,000 (30,000). "There’s always a shady side to business around here," he said. "But as for the terrorism stuff, that sounds like a complete load of rubbish."