Mary Brengel worked for Guy Banister for a short period in 1963. In May 1967, she wrote Jim Garrison a letter offering to be interviewed about her knowledge of what went on in Banister's office. Here is her letter to Jim Garrison:
Here is my transcription (please help fill in the blanks):
Dear Mr. Garrison:
I am aware from the publication in the newspapers of his picture, with an arrow pointing to his office door, that Guy Banister may possibly figure somewhere in the case you are building.
I worked in his office from the latter part of October until about the 10th of December, 1963, during which occurred several rather strange or unexplained (to me) things (however not associated with Cubans). If you feel that anything I might tell you could help to throw - [ , , ,] light on missing details, I would appreciate talking with you confidentially - though naturally I would like to stay out of "the limelight."
Mrs. Delphine Roberts worked much more closely with and a great deal longer for Mr. Banister than I - so if you are in contact with her and if she is speaking freely about the incidents that bring questions to my mind - then I could add nothing. I do question that she would speak freely and if she may have omitted mentioning any persons I might mention, I surely would not want her to know I offered information until after you had my information.
Is there a question about whether Mr. Banister's death in June 1964 was from natural causes? I do question this as well as the roles of others in connection therewith.
I am employed by Mathews, Bergman, Farrah + Associates Architects, as Office Manager and secretary to Mr. Mathews and can be reached at their office at 929 Howard Avenue - Third Floor - during working hours, Mon. thru Friday. Two office phone number are shown below.
There is, in fact, a small conference room in my office which might serve well for a short confidential talk.
Please understand I am convinced after Channel 4's presentation last night that you are seeking the truth and are - even though you know the truth -- being blocked on various details. I would hate to furnish information against anyone I consider a conservative particularly Mr. Banister, but as you, too, seem to feel the American people (and the world) deserve the truth about Kennedy's assassination, regardless of where that truth lies.
Only you can assess whether the facts I could provide are meaningful or are merely trivia which would naturally raise questions in the mind of a person doing temporary work for a private investigator.
Please let me know if I may be of assistance - preferably, of course, on a confidential basis.
Ms. Brengel clearly wanted to tell her story - she seemed very anxious to help the Garrison investigation. And so she met with two Garrison investigators at her home:
Note that she did not say one word about Lee Harvey Oswald - just like Delphine Roberts. Brengel's main suspicion was that Delphine Roberts might have had foreknowledge of Guy Banister's death.
Mary Brengel was also interviewed by the HSCA:
Brengel does not mention anything about Oswald being in Banister's office.
How do the conspiracy books treat Brengel? James DiEugenio writes in Destiny Betrayed:
He doesn't report that Brengel did more than "believe that both Banister and Roberts had some prior knowledge of the assassination." She told the HSCA that "she has wondered if BANISTER was not in Dallas on 11-22-63 and in fact was one of the men with a high-powered rifle there."
Here is Brengel's submission to the ARRB:
Funny how she gets the date of the assassination wrong (September 3,1963). Might this be age-related confusion?
Now, her statement to the ARRB does confirm what DiEugenio writes in Destiny Betrayed. But notice the difference between her initial statement to Garrison and her later statement to the ARRB. First, she says that Roberts got a phone call that Kennedy had been assassinated and that she should turn on the TV. It's not unusual for a detective agency to have a television in the office. In her second statement, Roberts brings a "pocket radio" to work on the day of the assassination, and then receives a phone call. There is no mystery of suspicion in her first statement. In her ARRB statement, she suspects Delphine Roberts of having advance knowledge of the JFK assassination and she also suspects that Banister might be part of it.
Her only suspicions in her Garrison statement was that Delphine Roberts might have advance knowledge of Banister's death.
The other DiEugenio claim is about Oswald:
This is true.
But note what Brengel said:
Delphine told me that both Lee Harvey Oswald and David Ferrie, as well as others who figured in the government hearings, had been in the office many times while I worked there.
But Brengel only worked for Banister from October 15, 1963 until December 15, 1963 and Oswald could not have been in the office then.
Furthermore, when did Delphine Roberts tell Mary Brengel that Oswald had been in the office? Probably after she talked to Anthony Summers -- perhaps she was cajoling Brengel to back her up.
Brengel told the HSCA that she started working for Banister in June, which is not what she told Jim Garrison in 1967. As shown above, she wrote a letter to Garrison in which she stated she worked for Banister from October to December 1963. So, her claim to the HSCA is probably the result of poor memory. Of course, if the June 1963 date is the correct date (which I doubt) then it is important to note that she did NOT see Oswald in the office during the dates at which he was supposedly there.
And here is Brengel's account from a 1979 interview which I found in the files of Gus Russo at Baylor University. Now, Oswald is left out totally and it's just David Ferrie that Roberts tells her she had seen:
Both Delphine Roberts and Mary Brengel are just not believable witnesses.