Michael from Muckrock writes, "While patiently noting that their anonymous tipsters thought Lennon was not a 'true revolutionist' because he used drugs, the FBI worked with INS over several years to bolster a case to deport the Beatles' musical genius."
"It's hard to tell why the FBI and INS were so intent on barring him from the country, particularly since his only offense was a prior cannabis conviction (in England, not even the US), but the Bureau took careful note of Lennon's financial support for anti-Nixon groups. He had donating $75,000 to the Election Year Strategy Information Committee which had the grand plan of holding rock concerts in protest of the Republican Convention. It's hard to tell how credible the Bureau's information on Lennon was, however. One file photo of him that the agency kept for identification purposes wasn't Lennon at all, but David Peel. Close enough for government work."
"Former member of the Beatles singing group" John Lennon's FBI file, part 1 [JPat Brown/Muckrock]