J. Edgar Hoover personally signed off on a wiretap of the activist’s Queens residence, citing his role as “a militant figure in the civil rights field”
The last section of Malcolm X’s 10,000 plus page FBI file concerns the Bureau’s electronic surveillance of the activist shortly before his death. For months, agents listened to Malcolm’s phone calls, photographed his comings and goings, and even considered bugging his Queens residence - only to hastily discontinue the operation for fear it would taint a potential conviction.
The file begins in March 1964 (the “JUNE” in the corner actually refers to the name of the file), shortly after Malcom had his falling out with the Nation of Islam.
Said falling out prompted Malcolm to found his own organization, Muslim Mosque, Inc. - and gave the Bureau what they felt was sufficient cause to begin electronic surveillance of Malcolm’s home.
https://www.muckrock.com/news/archives/2017/may/19/malcolm-x-wiretap/