Tiffany McInnis

They had been dating for just six months.

Weeks before Kim disappeared, they took a trip to Cozumel, Mexico.

Did you sense they were both in love?

Yes.

However, Detective Ball says he was suspicious of Weatherford, mostly because of what he didn't do the night Kim disappeared.

He saw her car in the parking lot, but he did nothing.

He didn't tell anybody.

He waited until the next day before he told anybody that he knew where Kim's car was.

And did you think to yourself, this man may be hiding something from me?

I suspect everybody.

Everybody's a suspect.

And that included coworkers and former bosses, like Frank McCormick.

This is an ID photo taken of him decades later.

Frank McCormick was a supervisor out in Mobile, and he worked in the same building as my mom.

Tiffany says McCormick, who was married, often came around their house and left Kim presents, like chocolates from Paris.

McCormick began sending Kim love letters, dozens of them.

He also sent disturbing photo collages.

These are grainy copies that were given to 48 Hours by investigators.

Esther said that Kim was upset about McCormick's bizarre behavior, but she didn't report him for fear of retribution.

Detectives say despite McCormick's obsessive behavior, he had an alibi.