The "Roswell Incident" (AKA the Crash at Corona) is a well-picked over story that goes something like this:
1) June 14, 1947, New Mexico rancher Brazel reports unexpected mechanical debris on his property.
He tells a UFO story to the local paper and police.
2) The cops call the Army, which sends over Major Marcel to collect the "alien artifacts."
3) The Army issues a press release about the "UFO."
4) Later, after more careful inspection, the debris is relabeled "as being a weather balloon and its "kite,""
The memo in question is from an FBI investigator Guy Hottel, written several years after this event. As wikipedia notes,
it isn't clear that this memo even refers to the "Roswell incident" at all.
Also, enjoy the retro-scifi techno-jargon contained in the memo:
"It is believed the [Army's radar located on the New Mexico base] interferes with the controlling mechanism of
the saucers."
At best, this memo is a report on hearsay. It is not direct evidence of a cover-up or even of recovered alien craft.
It is, in the neologisms of today, some government dude's blog post.
Don't thank me, Internet. I'm just doing my job.