* Official investigations: The Warren Commission, the primary investigation into the assassination, confirmed Oswald's employment at the book depository.
* Eyewitness accounts: Many people who worked at or near the building during Oswald's time there reported seeing him.
* Physical evidence: Oswald's work records and a photograph of him holding a rifle similar to the one used in the assassination were found at the depository.
It's important to note that while Oswald worked there, the exact details of his activities and motivations remain debated. Some theories suggest he may have been part of a conspiracy, while others believe he acted alone. However, his employment at the book depository is a well-established fact.