O.J. Simpson Juror: We Thought Marcia Clark and Chris Darden Were Banging!

Marcia Clark and Chris Darden blew the O.J. Simpson murder trial because jurors were more focused on whether they were doing the deed ... according to one infamous panel member.

Michael Knox was juror #620 -- the guy featured on 'The People v. O.J.' who got booted for lying about a prior conviction. He told us many jurors saw Marcia as unprofessional, partly due to the perceived sexual tension ... but also because some female jurors were offended by Clark's short skirts.

How offended? You gotta see the word he used to describe Marcia.

But Knox thinks Mark Fuhrman's lie about the "n-word" really sealed the deal for the defense. His take on the word is, umm ... something to see.