BOTHELL, Wash. - Detectives say a Web site called vampirefreaks.com served as a stalking ground for a savvy internet predator.

They say 30-year-old Sean E. MacMartin created a goth persona for himself on the Web site and searched for young girls online.

Within the past few months, he's been charged with five counts of rape of a child in the third degree in cases involving girls between the ages of 13 and 14. He coerced them into coming to his Bothell home.

Detectives fear there could be more victims.

"You've got very young girls that are impressionable, they're on the internet, they think they're safe on the internet," said Sgt. John Urquhart, of King County Sheriff's Dept.

The girls got to know MacMartin online. He used nicknames including Soroth, Darklord, and most frequently – Soth.

Eventually they agreed to meet in person at his home, believing the then 29-year-old was in his late teens or early 20s.

"I think he was real savvy in how he went about it," said Sgt. Urquhart. "He's a stalker. He's stalking young girls, he's using the internet to do it and when he does make contact with them he's grooming them, grooming them for sex and then luring them to his place."

Some of the underage girls had sex willingly,

But for at least one, it was not consensual.

In court papers, one alleged victim says:

"... when "Soth" was cooking he asked (the victim) if she wanted some wine with her dinner. (the victim) told "Soth" that she was fourteen. "Soth" said that there were no cops around."

After dinner, the victim says she fell asleep, then:

"... (the victim) said that she woke up to "Soth" biting her neck. (the victim) said that "Soth" held her hands above her head and sex with her even after she told him to stop."

MacMartin's attorney tells KING 5:

"Mr. MacMartin has maintained his innocence since Day One. Our investigation is still ongoing."

Charges have also been filed against MacMartin's roommate, Robert Schwarzinger, who is accused of having repeated sex with a 13-year-old girl.

Deputies say they're concerned there may be other young victims out there.

"Certainly anybody that does know this guy or has been contacted by him, even if nothing happened, we'd like to know about it," Urquhart said.

MacMartin was able to post his half million dollar bail and is currently out of jail.

Both men are scheduled to be arraigned on newest charges early next week.