Now, her father is sharing his agonizing story.

From the helplessness of waiting by the phone, to fears she might have met the "wrong person" in an Internet chat room.

Jerry Pease, of Rochester, did manage to track the web sites his daughter visited just before she disappeared, and what he found scares him.

"You go through periods where you feel like you're not going to see her again," Pease told KOMO 4 News.

Heather, 15, vanished after telling her Dad she was meeting some friends on her way to school on Tuesday.

"These are all the books and papers and everything we found that has anything written on them that might give us a clue," Jerry told us as he looked through his daughter's room.

The one clue Heather's father did find was on the family computer.

He now knows Heather had been visiting a dating website where she put her picture online.

Her distraught father is worried that someone much older may have engaged Heather at the site's online chat room, and may have been the "friend" Heather met on Tuesday.

"I don't know who, and that's the scary part," Pease said, "that we don't know who picked her up."

The Center for Missing and Exploited Children is starting a new National Ad campaign to educate kids and their parents about online chat rooms.

A new national survey shows teen girls are the primary targets of online predators.

"They're the best victims out there because they are emotion driven," Detective Malinda Wilson of the Seattle Police Department told KOMO 4 News, "they want closeness, they want relationships."

Jerry Pease isn't sure if his daughter's disappearance is tied to someone she met on the Internet.

Washington State Patrol computer experts plan to examine the family computer to see if they can spot any clues.

In the meantime, a heartbroken father busies himself putting up missing person flyers and hoping for any shred of good news.

"And, as time goes on," said Pease, "it gets more scary."

Heather's dad admits she did runaway once before, but he's quick to point out that was to her grandmother's house.

And, he says, she didn't take any clothes or personal possessions.