Verify? It was in the papers...
Honestly, it's happened countless times. There is, however, a national security issue involved and that has been the reason for the cover-up.
It is a pretty substantial risk, too, I understand that, but I think we have come to the point where we can protect ourselves, even from this new technology.
Part of the risk comes from the development of a new, compact, highly efficient form of isotope separator. This technology is used to manufactore vehicle components on sight and allows you the ability to replace broken parts with nothing but soil or water as a raw material. Pretty cool, huh?
We have this technology in the public domain now, but the alien version is much smaller and more powerful. (Just do a search for Laser Isotope Separation - L.I.S.)
The national security issue is this - A person could use this technology to extract any isotope for any purpose, not just aluminum, but maybe plutonium, for example.
(that would be bad)
And that's just how you make a saucer, we havent even started on how saucers have disabled our ICBM's during flight tests...