Was Marina Oswald Involved in the JFK Assassination?

Here's an article I just came across in the papers of Dick Russell. It's from September 3, 1975 and was most probably in the New York Daily News, which is where Dick Brass worked.

Fletcher Prouty and Richard Sprague embarrass themselves in front of everybody by claiming:

No shots from the sixth floor window of the TSBD.
No one took the backyard photographs of Lee Harvey Oswald.
Marina Oswald might have been in on the plot.
Secret service policy only allowed for a minimum speed of 44 mph in a motorcade.
The umbrella man may "have signaled the assassination."

Here is the press release for Prouty's article:

You can read "The Guns of Dallas" here. The article included this:

and this:

Previous Relevant Posts on Fletcher Prouty

James DiEugenio's Lame Excuses for Fletcher Prouty

Fletcher Prouty Talks to the ARRB

A summary document of his interview with the ARRB

Transcript of Fletcher Prouty's Interview with the ARRB

Fletcher Prouty and Army Intelligence in Dallas

Another summary document from the ARRB about Prouty's allegations and army intelligence.

Was Fletcher Prouty an Antisemite?

Prouty had some very unsavory relationships with antisemitic groups.