No one corrects her, which must mean Rossmiller has said it right, in the right spot. She's elated. They're buying me as one of them.

Having digested a clutch of Arab novels, Rossmiller uses the devices of fiction to invent characters she can be on the Web.

She must be specific and nuanced to be believed, she thinks, but one persona is not enough.

It's a control thing, she decides. If I can have an effect on them, then maybe I can stop the evil they do.

Rossmiller begins to fill notebooks with detailed aspects of her made-up characters - names, photos, occupations. Some are good at bomb-making. Others are facile with small weapons.

I've got some real doozies here, Rossmiller says to herself as she reviews her ensemble of grim operators, her own fictional collection of serial killers.

Soon Rossmiller has created around three dozen "people." She searches Web sites for obituaries with pictures, then alters the images so relatives wouldn't recognize them.

The photos are mostly for herself, to keep a picture in her head of whom she's supposed to be, a sense of her character. Once in a while, someone asks to see whom he's talking to, and Rossmiller can oblige.

She researches mosques in Jordan and Pakistan to learn their street locations and the names of their imams. This way, she can make authentic references during online chats.

After several months, she has developed quite a correspondence with dozens of people who seem to believe she is whoever she says she is.

Many of the men with whom she communicates seem to be uneducated and indigent, judging from their poor language and computer skills.

They don't have Web access at home. So they crowd into Internet cafes to chat and bluster, Rossmiller learns by reading the Internet protocol addresses. Over time, she has become so precise with her computer sleuthing that she believes she can tell within a block in which cafe in Abu Dhabi, for example, they're gathered. Her method is to examine details such as computer document properties, which include the cafe name and computer work-station number.

All these young men seem to know is the fanatical side of Islam, and they believe in martyrdom for the cause.

Ultimately, they trust Rossmiller because they're convinced they're always interacting with people like themselves.

To her uncomfortable surprise, Rossmiller discovers that impersonating extremists is getting easier. That's a little scary, she says to herself. What's inside me that lets me do this?

Sometimes, online, Rossmiller becomes an eldest son whose father has died and passed on to him the responsibility of the entire family. The ruse garners respect and sympathy.

Other times, she plays the unstable, lost kid from Amman who wants jihad, but has no idea how to bring it about.

Often, she is the raging bull taking over the chat room.

It was that way with the Stinger missiles.

"I have Stingers to sell," a Jordanian writes to Rossmiller in July 2002. He says he has gotten them from a source in Pakistan.