Did ex-NFL player, girlfriend, kill millionaire?

Former linebacker Eric Naposki talks to "48 Hours" in first TV interview about 15-year-old Orange Co., Calif., murder case

Bill McLaughlin's fiancee, Nanette Johnston, had a big secret: Eric Naposki, a 6'2", 250-pound professional football player for the NFL.

Naposki, a linebacker for the New England Patriots and the Indianapolis Colts, among other teams, was certain in December of 1994, that Nanette was his girlfriend.

He was even making plans to propose.

"You wanted to marry Nanette?" Roberts asked Naposki.

"I did," he replied.

"Do you think she really loved you?"

"She appeared to back then."

"Nanette seemed madly in love with him," Naposki's sister, Angela Licata, said. "I liked her. She had two small children - they were wonderful children... We thought she was the one for Eric because she was strong and she was intelligent. And we thought it was a good match."

Photos: Who is Nanette Johnston?

Dave Matthews couldn't believe his high school buddy was smitten.

"Eric, back then...you know, he's a good looking, charming funny guy with great energy," Matthews said. "I mean, he's a tough one to fall in love because he dates a lot."

But with Nanette, things were different. "This wasn't just a regular girl," said Matthews.

Naposki's former roommates, Rob Frias and Leonard Jomsky, agreed.

"She was a bombshell," Frias said. "She was very attractive. It was hard to miss her."

"She was beautiful," Jomsky added. "I mean without a doubt. She was a really, really pretty girl."

But to Naposki, there was much more to Nanette than her looks.

"She graduated college early," Naposki told "48 Hours." "She wrote business plans for a living."

"She had this concept for...like prototype design for a device...it separates plasma from blood, it's really cool," Matthews explained. "They winded up selling it making tens of millions."

Nanette told them she took her invention to her boss, Bill McLaughlin.

It was Nanette's tale of how she became very rich and how McLaughlin went from being her boss to being her business partner.

"From the very beginning, she told me exactly what she was doing with Bill McLaughlin, as far as a mentor and as far as a business relationship. And it sounded really good," Naposki told Roberts.

"You never suspected that she and Bill McLaughlin shared an intimate relationship?" Roberts asked Naposki.

"I never once suspected," he replied. "Bill was an investor and Nanette also took part in his investments. ...she would tell everyone the same story."

Not only did she take credit for Bill McLaughlin's work, but Nanette claimed his money was her own.

"She came over with a new car one time - a dark green Cadillac," Frias recalled.

Bill McLaughlin had bought it for her, but that's not what Nanette told them.

"She said she went out and wrote a check somewhere in the neighborhood of $60,000," Frias continued.

Nanette told them she and her business partner were investors in high-end real estate.

"...that she owned a $5 million beach house in Newport," said Naposki.

Naposki says Nanette told him she also shared a million-dollar home with her colleague, Bill, where they had separate bedrooms.

To Eric Naposki, she was clearly a self-made success story - something he desperately wanted to be. But his football career was in jeopardy.

"In Giants Stadium... I'm making a sack and my foot twisted and I popped the arch in my foot," he explained.

Years of playing professional football was taking a toll. In the early 1990s, Naposki was trying to figure out what to do next.

"[I] started programs at the gym working with kids, trying to get their...athletic ability improved. ... Started a security company," he said.

And then, just two weeks before Bill McLaughlin's murder, Naposki got another job running security at the Thunderbird nightclub. It was located less than 200 yards from McLaughlin's home where he was killed.

Asked how he learned that Bill McLaughlin was murdered, Naposki told Roberts, "Nanette told me. ...She was shaken up. She was absolutely shaken up. ...I asked her, 'Was it a business deal?' ...And she went right to the business deal with ex-business partner Hal Fischel."

Naposki had heard about the animosity between the business partners, so Nanette's story sounded plausible. But then a week after the murder, everything changed.

"I notice there's a car following me," he said.

It was the police.

"They brought me to an interview room and started throwing questions at me," Naposki told Roberts. "Like, 'what's your relationship with Nanette?

Detective: What's your involvement or relationship?

Eric Naposki: Nanette's a pretty good friend of mine.

"He was very evasive," said Detective Voth. He remembers Naposki wouldn't give them a straight answer.

Detective: Would you describe it as a dating relationship, a boyfriend-girlfriend?

Eric Naposki: I wouldn't say a, a solo total, like I have girlfriends, you know.

"You weren't very honest with investigators," Roberts commented to Naposki. "If you're an innocent man, why would you do that?"

"I'm an innocent man now...there's no...handbook when you're being looking at as a suspect in a murder case," he replied.

Naposki was not forthcoming about Nanette and evasive when questioned about other things.

"He started off by saying he had no firearms," said Det. Voth.

Eventually, Naposki admitted to having a 9mm gun.

"What were you thinking when you heard he owned a 9mm?" Roberts asked Voth.

"I knew that...a 9mm was used in this crime," he replied.

Naposki refused to tell investigators where the gun was.

Detective: Where is your 9mm?

Eric Naposki: I have no idea.

Detective: You have no idea

Eric Naposki: That's my statement.

Video: Watch more of Naposki's interrogation

"Why weren't you truthful about the 9mm with police?" Roberts asked Naposki.

"I think I was just scared," he replied. "Because I didn't buy that 9mm for myself. ...That was Nanette's 9mm Beretta. ...I was scared to start throwing around, 'that's Nanette's gun. You know, go look at Nanette.' ...that would have been really like just pointing the finger."

Especially since, at the time, Naposki said he was convinced she had nothing to do with Bill McLaughlin's murder. And that the police were trying to frame them both.

"They're telling me, 'Well there's this relationship going on that you don't know about. And then she's telling me, 'there's no relationship that you don't know about,'" Naposki explained.

"Eric called home," his sister, Angela Licata, recalled. "He was hysterical crying and he said...'You know they think I killed this guy. They think I killed him."