He obtained official Italian documents that date back to the 30's, specifically 1936 where the then Fascist Government was handling and documenting UFO sightings. Mussolini was very concerned about these unexplained craft because of the effect they might have on the Italian Air Force.
The documents talk about elongated craft expelling smaller flying saucer type UFOs. One sighting happened over the skies of Venice. The Air Force attempted to intercept these craft but could not as they were too fast.
Recently the Chief of the Intelligence Office of the Italian Air Force, General Olivero, spoke about this subject saying that the problem of UFO's exists and that the Air Force has been dealing with it since 1978.