Both Grissom’s son and widow believe he was murdered. And there is also a very odd story about a Safety Inspector who died in a very unusual way.
I will add, or note again, as I have in the past, that for sure Buzz Aldrin, Gordon Cooper and Edgar Mitchell have gone on record as having either first hand, or reliable second hand knowledge of extraterrestrials. Aldrin saw one, then recanted, then got a bit foggy. Cooper said he saw two, on two separate occasions, one of which landed, and of which film footage was taken, and then confiscated. Mitchell was merely a conduit for a lot of witnesses, who sought him out because he was not afraid to speak publicly.
There may be nothing here, but there is certainly plenty of fertile material to work on here for imaginative minds.