---
alias:
- Joseph A. Oster Jr.
- Joe Oster
born: 1928-11-18
category: JFK Assassination
created: 2026-09-21
location: New Orleans, Louisiana
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.
tags:
- Person
- JosephOster
- PrivateInvestigators
- NewOrleans
- GuyBanister
- SouthernResearchCompany
- DavidFerrie
- ARRB
updated: 2026-09-21
---

Joseph A. Oster Jr. was born in [New Orleans](/places/new-orleans/) on November 18, 1928, attended Nichols High School, served in the armed forces after the [Second World War](/events/world-war-ii/), 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 [CIA](/organizations/central-intelligence-agency/) security file, lists him as an associate of "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](/places/shreveport-louisiana/)," 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](/people/guy-banister/), of the [David Ferrie](/people/david-ferrie/) investigation, and of the [Clay Shaw](/people/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](/people/william-gurvich/), the city police, and the local office of the [FBI](/organizations/federal-bureau-of-investigation/). 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](/organizations/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](/places/houston/). He said he once saw [Lee Harvey Oswald](/people/lee-harvey-oswald/) handing out his [Cuba](/places/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](/events/hsca/) "everything they wanted" from his files, on both the Kennedy and the King cases, and the committee had returned the papers.[^2]

[^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.