In the PDF notes of "Reclaiming History" it says:
The only other person who possibly connects Oswald to Banister, though he
doesn’t claim to have seen the two in each other’s presence, is a former investigator
for Banister, George Higgenbotham. Higgenbotham told a DA investigator during
a series of interviews on April 12, 16, and 17, 1968, that one time he was kidding
Banister about sharing a building with people passing out leaflets on the street,
and Banister said, “Cool it. One of them is one of mine.” Note that there’s no reference
to Oswald, or what the leaflets even said, and Banister and Higgenbotham
were talking about more than one person passing out leaflets, whereas Oswald, with
the exception of the time in front of the Trade Mart, was the only known person
passing out Fair Play for Cuba leaflets. Further, Higgenbotham worked for Banister
in 1960–1961, and Oswald wasn’t even in New Orleans during this period,
though Higgenbotham continued to have some social contact with Banister after
that. The information Higgenbotham furnished the DA’s office, possibly because
he was facing a charge of marijuana possession, was further suspect. For instance,
he said a fellow gay (Higgenbotham was gay), Eddie Porter, told him that Oswald
was a “hustler” on Royal Street. The DA investigator (whose identity is not clear
from the two-page, typewritten document) who interviewed Higgenbotham also
obviously had questions about the latter’s credibility, saying that “much of what
George said was difficult to orientate,” adding that “I was never sure whether what
he said was meant to be bait or not.”
And then from the website http://whokilledjfk.net/oswald1.htm it says:
Historian Dr. Michael L. Kurtz was a student at Louisiana State
University in New Orleans during the 1962-63 school year. In 1958,
LSU-NO, now the University of New Orleans, became one of the first
racially integrated universities in the South. One of the most vocal
opponents of that decision was W. Guy Banister. It is now common
knowledge that Banister recruited LSU-NO students to spy on fellow
students and faculty members, and Banister himself made frequent visits
to the campus to make his feelings known.
One day in May 1963, Michael Kurtz attended an informal meeting in an
unoccupied LSU-NO classroom where Guy Banister debated a number of
students on the issue of integration. Banister was introduced by an LSU
student named George Higganbothan. Kurtz knew of Banister; he'd seen
him on campus on perhaps a half-dozen occasions to this and would see
him a few times more. Guy Banister brought a young man to the meeting with him;
Banister introduced the young man as Lee Oswald. Banister debated
integration with the students, arguing for a return to full segregation
and criticizing the group for attending an integrated school. While
Banister tangled with the pro-integration collegiates, Oswald seemed to
fade into the background, and -- to the best of Kurtz' recollection --
said nothing. "If he did," Dr. Kurtz says, "I didn't hear him" (Author's
interview of October 5, 1998).
George Higgenbothan told Kurtz that Oswald and Banister made a second
visit to LSU, however, and the second time it was the alleged leftist
OSWALD who argued passionately against desegregation (Interview with
Michael L. Kurtz, December 2, 1998). Higgenbothan had told the Orleans
Parish DA's office in 1967 that he indeed had known Oswald (Garrison
files).
Who is telling the truth - Vincent Bugliosi or WhoKilledJFK.net when they state that Garrisons files state that Higgenbothan did or did not know Oswald and visually see him? Its noteworthy that Higgenbothan was gay (according to Bugliosi). Oswald keeps appearing to be seen in the company of gay people in New Orleans.
Mr. Kurtz wrote an article on Oswald in 1980 (linked below) and supposedly later a book on the assassination (I can't find the source for this one). In neither publication did he mention seeing Oswald with Banister at any time. He does mention Oswald being seen by unnamed people with Banister. But again he himself is never mentioned as one of those sources.
It is only later in his 2013 book "Crime of the Century" that he says one of the sources was himself. I find it, well, strange that he wold never mention earlier that he HIMSELF saw Oswald with Banister.
It's certainly conceivable to me that Banister saw Oswald outside the Trade Mart distributing his flyers or advocating for Castro and was curious about him. So wouldn't he talk to Oswald, try go find out what he was up to and who (if anyone) he was associated with? That is far different, of course, than what Kurtz said he saw them doing.
Banister's secretary and fiance Delphine Roberts told the Garrison investigators that he would often talk to groups on the left or right as part of his job gathering intelligence for his work. She also never mentioned during the interview seeing Banister with Oswald or him mentioning
after the assassination about knowing Oswald. Years later however she said that Oswald regularly visited Banister's officer.
In any case, Kurtz's 1980 piece is here:
http://mcadams.posc.mu.edu/ngarchive/4231952.pdf