Primary Source: FBI Files on Martin Luther King, Jr.

Martin Luther King, Jr., speaking at a podium at the March on Washington
By White House Staff Photographers. Public Domain, https://commons.wikimedia.org/w/index.php?curid=546670

Full text access to the FBI’s file on the assassination of Martin Luther King, Jr. is available on the GALE platform. “The 44,000-page case file … documents the bureau’s role in finding Ray and obtaining his conviction. The file also includes background information amassed by the FBI on Dr. King’s social activism.”

Black Freedom Struggle in the 20th Century: Federal Government Records, on the Proquest platform, includes the two FBI files on Martin Luther King, Jr. Part 1
“details the heavy surveillance and painful harassment that J. Edgar Hoover’s FBI directed against America’s foremost civil rights leader throughout the 1960s.” Part 2 consists of verbatim transcripts and detailed summaries of telephone conversations between King and one of his most trusted confidants, Stanley D. Levinson.