Francis Ridge:
Our thanks go to Wendy Connors and her Faded Disc Archive (formerly Project Sign Research Center) for the following documents which were never available to the public before.

Wendy Connors:
These are missing documents regarding the Mantell incident. These are not in the Blue Book microfilms.

  Mantell Doc. 1 - NEWS RELEASE, PIO, Clinton Co. Airfield, Ohio - Jan 8, 1948
  Mantell Doc. 2 - Jan 14, 1948 letter to CO, 332nd Fighter Wing, from Lockbourne AFB
  Mantell Doc. 3 - Jan 14, 1948 letter to CO, 332nd Fighter Wing, from ATC Boudreaux
  Mantell Doc. 4ab - Jan 14, 1948 letter to CO, 332nd, from VHF/DF Pickering
  Mantell Doc. 5 - Jan 14, 1948, Col. McCoy's request for report
  Mantell Doc. 6 - Jan 20, 1948, Confidential Affidavit, Cpl. Hudson
  Mantell Doc. 7 - Jan 21, 1948, Confidential Affidavit, S/Sgt. Haag

Ruppelt notes which mention the Mantell incident:
[Major] General Cabell presided over the meeting, and it was attended by his entire staff plus Lieutenant Cummings, Lieutenant Colonel Rosengarten, and a special representative from Republic Aircraft Corporation. The man from Republic supposedly represented a group of top U.S. industrialists and scientists who thought that there should be a lot more sensible answers coming from the Air Force regarding the UFOs. The man was at the meeting at the personal request of a general officer. 

Every word of the two-hour meeting was recorded on a wire recorder. The recording was so hot that it was later destroyed, but not before I had heard it several times. I can¹t tell everything that was said but, to be conservative, it didn¹t exactly follow the tone of the official Air Force releases, many of the people present at the meeting weren't as convinced that the 'hoax, hallucination, and misidentification' answer was quite as positive as the Grudge Report and subsequent press releases made out. 

Toward the end of the two-hour conference a general asked Lieutenant Cummings to review the activity of the UFO investigation for the past year and a half. Maybe it was just a lack of sleep, or maybe it was just Cummings, but the general got the straight answer, for all practical purposes the project was dead. Then Cummings proceeded to elaborate on the details, the attitude at ATIC, the opposition to his reorganizing the project, and the methods of processing reports. Lieutenant Cummings didn't miss a point. He later told me that all of the generals and about three fourths of the full colonels present at the meeting turned the shade of purple normally associated with rage while a sort of sickly grin graced the faces of the remaining few. Then one of the generals on the purple-faced team glared at the sickly-grin team and cut loose. 

The first thing the general wanted to know was, 'Who in the hell has been giving me these reports that every decent flying saucer sighting is being investigated?' 

Then others picked up the questioning. 

'What happened to those two reports that General ___              sent in from Saudi Arabia? He saw those two flying saucers himself.' [That case actually occurred after this meeting took place during the next year of 1952 to a General E.M. Day, apparently the case that was so discussed at that meeting was the Mantell Incident. Because Ruppelt made such an effective argument in his book that the Mantell Incident was not UFO related, he probably substituted the Saudi Arabia sighting so as not to bring the issue of Mantell up again.] 'And who released this big report, anyway?' another person [we now know this was Major General Cabell] added, picking up a copy of the Grudge Report and slamming it back down on the table. 

Source: "Captain Edward J. Ruppelt" by Michael Hall and Wendy Connors