Dr. Robert Sarbacher was an American physicist and consultant to the DOD (Dept. of Defense).
In 1950, Sarbacher reportedly told a group of Canadian scientists that the U.S. had recovered a crashed extraterrestrial craft, including bodies, and was attempting to reverse-engineer the technology but to no avail.
In a letter dated November 28, 1983, Dr. Sarbacher confirmed that he had indeed made such statement.
Dr. Sarbacher's 1983 letter can be read HERE.
Dr. Robert Sarbacher - A Key U.S. Contact
Of Roswell & Rockets: The Secret V-2 Flying Saucer Film
*Addendum: To see an actual copy of the letter, click HERE.
Note: I would strongly advise readers to visit the link above and read what Dr. Sarbacher had to say about the debris and the aliens.