EXCLUSIVE: O.J. Simpson Shocker — Slaughtered Nicole Brown Simpson's Lover Remembers Menacing Moments With NFL Killer Two Years Before Brutal Slayings

One night outside her house, he thought he smelled her perfume, "as if she had been standing there," he writes in his new memoir, The Forgotten Briefcase.

Several weeks later, Nicole called him to tell him a neighbor had seen O.J. skulking around in the bushes outside her home that night.

He also later discovered Nicole sometimes wore Paco Rabanne men's cologne, as did her ex – and he realized it was O.J.'s scent he had detected.

Nicole called the Pro Football Hall of Famer out on coming to the house when she was there with someone, Perrulli said.

But O.J. claimed "he just happened to be driving by and wanted to make sure everything was okay. He also said he really didn't have a problem with me. He said he felt I was a gentleman," Perrulli added.

In another sinister incident, he was running with Nicole and another friend when they spotted O.J. with his and Nicole's two children, Sydney and Justin, at a local market.

"Our friend seizes up and said, 'Joseph, whatever you do, keep running,'" he recalled.

"Before I passed, it almost felt like [O.J.] marked me. His glare was penetrating."

Afterwards, he said, Nicole "was very upset. She felt like he followed her with the children to make her look bad."

But the red flags continued and Perrulli broke off their romance after a few months.