---
category: "JFK Assassination"
tags:
  - Person
  - JosephOster
  - PrivateInvestigators
  - NewOrleans
  - GuyBanister
  - SouthernResearchCompany
  - DavidFerrie
  - ARRB
alias:
  - Joseph A. Oster Jr.
  - Joe Oster
summary: "New Orleans private detective who left Guy Banister's agency to manage the local office of Southern Research, investigated David Ferrie for Eastern Air Lines, and went to Ferrie's apartment with the district attorney's men on November 22, 1963."
born: 1928-11-18
location: "New Orleans, Louisiana"
created: 2026-09-21
updated: 2026-09-21
---

Joseph A. Oster Jr. was born in [[New Orleans]] on November 18, 1928, attended [[Nichols High School]], served in the armed forces after the [[World War II|Second World War]], and spent six years as a detective in the [[New Orleans Police Department]] before going to the [[Pendleton Detective Agency]]. A credit report of July 25, 1960, copied into a [[Central Intelligence Agency|CIA]] security file, lists him as an associate of "[[Guy Banister Associates|Guy B------ Associates]], Inc." and as vice president for the past year and a half of "Southern Research, Inc., whose home office is in [[Shreveport, Louisiana|Shreveport]]," a firm of ten or twelve employees. The [[Metropolitan Crime Commission]] held a report on him dated April 5, 1960.[^1]

### Interview of 1996

[[Philip Golrick]], a lawyer for the [[Assassination Records Review Board]], telephoned Oster on January 18, 1996, in search of the files of [[Guy Banister]], of the [[David Ferrie]] investigation, and of the [[Clay Shaw]] defense. Oster had none of Banister's papers. "If you got hold of those, you'd really have something," he said, and added that it would have taken a moving van to carry them. He named as possible holders Banister's employee [[Delphine Roberts]], the investigator [[Joe Marlborough]], [[William Gurvich]], the city police, and the local office of the [[Federal Bureau of Investigation|FBI]]. He called Banister "the Chief" and described him as polished and articulate and not a heavy drinker. He said he had left him for the [[Southern Research Company]] "because Banister was getting more involved in controversial political causes, to the detriment of attracting paying clients."[^2]

Oster said he had investigated Ferrie for [[Eastern Air Lines]] in 1962 and 1963, and that on the night of the assassination he went with the district attorney's investigators [[Raymond Comstock]], [[Louis Ivon]], and [[Lynn Loisel]] to Ferrie's home, where they found [[Layton Martens]] and another young man. Ferrie had gone to [[Houston]]. He said he once saw [[Lee Harvey Oswald]] handing out his [[Cuba]] leaflets in the summer of 1963, and that the police sergeant who arrested Oswald and [[Carlos Bringuier]] that August was a good friend. He left Southern Research in the middle 1960s. He "stated that neither he nor Southern Research had worked for the Clay Shaw defense team," which the records of Shaw's lawyer contradict. He had given the [[House Select Committee on Assassinations]] "everything they wanted" from his files, on both the Kennedy and the [[Martin Luther King Jr.|King]] cases, and the committee had returned the papers.[^2]

### Footnotes

[^1]: Central Intelligence Agency, report of investigation, September 13, 1960, JFK record 104-10109-10379, p. 14; Assassination Records Review Board, memorandum on records of the Metropolitan Crime Commission of New Orleans. Mary Ferrell Foundation archive.
[^2]: Golrick, Philip D. Memorandum to David G. Marwell, "Phone Conversation with Joseph Oster," January 19, 1996, Assassination Records Review Board electronic files (OSTER.WPD). Mary Ferrell Foundation archive.