Although Marina initially supported the Warren Commission's findings, she ultimately expressed doubts and advocated for Oswald's innocence.

At a party in February 1963, George de Mohrenschildt introduced the couple to Ruth Paine, a Quaker and Russian language student.

[citation needed] In January 1963, Oswald mail-ordered a Smith & Wesson .38 revolver and then, in March, a Mannlicher–Carcano, the John F. Kennedy assassination rifle.

[4] Later that month, as Marina told the Warren Commission, she took photographs of Oswald dressed in black and holding his weapons along with an issue of The Militant newspaper, which named ex-general Edwin Walker as a "fascist."

[6][7] The photo that had been given to de Mohrenschildt was signed and dated by Lee Oswald on April 5, 1963, five days before the attempted assassination of General Walker.

de Mohrenschildt eventually revealed this photograph to the House Select Committee on Assassinations (HSCA) in 1977, shortly before committing suicide.

Ruth Paine learned from a neighbor that employment was available at the Texas School Book Depository, and Oswald was hired and began working there on October 16, 1963, as an order filler.

"[15] Marina came to live in a hotel with business adviser, James H. Martin, who said that were "a few threats on her life mixed with the thousands of letters of sympathy she has received".

[16] After the assassination of Kennedy and the arrest of her husband, Marina was under Secret Service protection until she completed her testimony before the Warren Commission.

[17] She testified that she "had never heard anything bad about Kennedy from Lee" and that while in Russia, Oswald told her he would vote for Governor John Connally when he returned to the United States.

[26] On June 1, 1965, she and electronics worker Kenneth Jess Porter travelled to Fate, Texas, and were wed by a justice of the peace.

[44] In 2018, Marina was contacted for the theory that the unidentified "prayer man" filmed on the steps of the Texas School Book Depository during the assassination by Dave Wiegman, Jr., of NBC, and James Darnell, of WBAP-TV, was Oswald.

Ed Ledoux phoned Marina after Stan Dane had sent enlargements of the Darnell and Wiegman films showing the "prayer man" figure.

[citation needed] Marina's daughters also gave a few interviews, in which they expressed scepticism regarding Oswald's guilt though they also say they just want to know the truth.