Click Here to listen to Dan's report

Click Here to listen to Dan's complete interview with Mike Gilbert

"When I found out Nicole was murdered, the first thing I thought was 'he finally did it'."

Mike Gilbert, O.J. Simpson's former marketing agent, says this with a matter-of-factness that is at first off-putting.

"He finally did it," Gilbert repeats, his voice not even quavering a little as he recounts his firsthand experience with one of the most notorious crimes of the past century.  In his new tell-all book How I Helped O.J. Get Away With Murder, Gilbert calls June 12, 1994 the "day the world stopped."

This isn't an understatement, since Gilbert, one of Simpson's closest confidants and most trusted advisers, suddenly found himself caught in the middle of a veritable Armageddon of shock, then intrigue, and then outright hatred.

"We the jury in the above and titled action find the defendant Orenthal James Simpson not guilty of the crime of murder."

With that matter-of-fact verdict, everything in Gilbert's world changed, and he had a front row seat to history.

"I sat with him in that attorney room [during the trial] every day for a year and a half," he said, adding that a few months later O.J. made a shocking confession to him.

"He had been smoking pot and drinking, and I gave him some Ambien to help him sleep.  It was just a moment where everything seemed right that maybe it would be good for him to be able to talk about it if he wanted to talk about it, and if not he'd just say, 'Mike, I don't want to talk about this'."

But Gilbert claims in his book that O.J. didn't, so he finally worked up the courage to ask him what happened that night.

"He took a deep breath and leaned back and then forward again on the couch and  looked at me and asked what I thought happened," Gilbert recalled.  "I said, 'You know, O.J., I believe that you went [to Nichole's apartment] and you killed her, I believe you did'."

"At that point, I was waiting for him to stop me and say 'Mike, come on, you know I couldn't do that.  I loved Nicole.'  But he never stopped me.  He just sat and watched me."   

Then, after what Gilbert remembered felt like an eternity, O.J. admitted to going to Nicole's place and that "she opened the door with a knife in her hand."

"He said, 'Mike, if she didn't answer the door with that knife, she'd still be alive'."

Gilbert claims that O.J. didn't' say any more, but didn't have to.  They both knew exactly what he meant.

Gilbert stayed on as Simpson's agent for a few more years, but now blames himself for helping him get away with murder, particularly before O.J. had to try on the infamous bloody gloves.

"I said, 'If you're worried about the gloves fitting or not fitting, just don't take any arthritis medicine, don't take any aspirin."

Simpson, who had arthritic hands from his football days, would often experience painful swelling when he would go without his medication.

"That's why the gloves didn't fit, because for those several days leading up to him trying the gloves on I would imagine that he took my advice and didn't take any arthritis medicine, didn't take any aspirin, didn't take anything."

With that, Gilbert now claims, "If it doesn't fit, you must acquit" was born.

His claims are indeed sensational, and for some too sensational to believe.  O.J.'s attorney Yale Galanter calls Gilbert a "delusional drug addict who needs money."

"That's expected," Gilbert counters.  "I said things like that to O.J.'s haters all the time.  But the bottom line is, I can pass a drug test.  I can pass a lie detector test.  I doubt O.J. could do either."

In the absence of either, can his claims be believed?  Is Mike Gilbert a guilt-ridden former enabler looking to clear his conscience or a debt-ridden huckster looking to sell books?

That's a verdict the public will have to reach for itself.