More than ten years ago, my late friend and mentor Sherman H. Skolnick wrote that “unlike the American CIA set up by a charter, the FBI HAS NO STATUTORY BASIS TO EXIST. It was simply created out of the mists and vapors swirling around the Justice Department, considered by some, a nest of vipers.” 
I don’t think the CIA has much of a legislative charter, per se. Although it came into being due to the National Security Act of 1947, its duties were supposed to be limited. There was no specific provision for covert political operations spelled out in the 1947 Act. And certainly the CIA was never envisioned as operating domestically. And yet, in 1963, the CIA’s “domestic division” had the audacity to appear.  
So not just the FBI was created out of the mists and vapors.
For awhile many years ago Mr. Skolnick emphasized in several reports that the FBI has no charter. Now, subsequent to the Valentine’s Day Parkland Shootings, with the FBI being criticized for ignoring warnings about alleged shooter Nikolas Cruz, Skolnick’s reports about the FBI not even having a legal charter to exist came to mind. Could this be true, that the FBI has no charter? I decided to look into it.
Confirming Skolnick’s reports is an article from Newsweek dated May 17, 2017: “The FBI has no legislative charter setting out its mission or responsibilities.” 
For decades, during the reign of J. Edgar Hoover, the original “FBI” Director, the prowling organization had no charter! This embarrassment was bandaged by President Jimmy Carter in 1979. On July 31st of that year, Carter transmitted to the U.S. Congress “the FBI Charter Act of 1979, which will provide the first comprehensive Charter for the functioning of the Federal Bureau of Investigation.” It was a “legislative proposal” from Carter. 
However Carter’s legislative proposal apparently was not enacted, since Newsweek reported in 2017 that the FBI has no legislative charter. 
——- Sources ——-
 “The Government-Criminal Connection – Part 3”, by Sherman H. Skolnick. No date given. http://www.apfn.org/skolnicksreport/g-cconn3.html
 The Invisible Government, by David Wise and Thomas B. Ross. New York: Random House, 1964.
 “CIA Is Expanding Domestic Operations”, by Dana Priest. The Washington Post (online), Oct. 23, 2002. https://tinyurl.com/y9sphx8x
 “Comey’s Ouster Brings a Chance to Clean Up the FBI”, by Emily Berman. Newsweek (online), May 17, 2017. http://www.newsweek.com/comeys-ouster-brings-chance-clean-fbi-610189
 “Presidential Statement: Carter Details FBI Charter”, https://library.cqpress.com/cqalmanac/document.php?id=cqal79-861-26160-1182934