Once upon a time, in the 1950's, the U.S. Government alone agreed to a pact with the race of the Homogreys. In exchange for advanced technology, the Greys were allowed a quota of abductees to be experimented on, harvest for genetic material, in a stasis where there would be no memory of the events. Before the 60's it appears that the Homogreys started violating this treay and began not only to exceed their limited amount of abductees, but were also mutilating other life forms and leaving blatant evidence of their encounters.
The U.S. Government with its inferior power and technology, could only try to further deepen this attempt at this pact.
In the past 10 years, due to the Freedom of Information Act, files from the U.S Navy and testimonies of military officers have become declassified. Sporadic but consistent information of this pact has been mentioned in recent files.
I'll get back to you on names, files, dates, and specifics later.