A Web site address pops up in one of the chat rooms he logs into. It directs him to an innocent-looking site. However, authorities say they are called "porn bots," which can take over a computer and boot up a number of explicit sites or plant a computer virus.

Shockingly, ICAC agents said they monitor a number of highly sexual chats that take place during regular business hours from adults who are sitting at their office desks.

"If employers had any idea," McQuiston says.

No safe place

Cases begin in any manner of chat rooms — even religious-themed ones.

"You can go into a room that talks about antique cars, a room that's about sports, you can go into a room that talks about employment opportunities. Eventually they'll all want to talk about sex," he said. "The only room that we've found in the seven years of being in operation that there is no sex talk is the 'Star Trek' room."

The conversations start in a chat room and then break off into instant message conversations.

Like anyone else online, McQuiston keeps a "buddy list" with the names of supposed "friends" (mostly male) he has messaged over days, weeks and even months. In reality, these are people being scrutinized very closely as potential child sex predators.

The typical Internet sex predator can't be described.

"We've arrested cops. We've arrested firefighters. We've arrested doctors, a psychiatrist and homeless people going to the library and using computers there," ICAC Capt. Chris Ahearn said.

Some who are arrested bail out of jail and log back on and begin chatting again, never suspecting they're talking to a cop.

McQuiston's fingers move quickly on the keyboard, responding to as many as a dozen instant-message conversations at once. In each one, he is posing as an underage child.

McQuiston responds to a number of people who think he is a preteen child. He uses ages ranging from 10 to 17.

"Asl," one writes.

It means "age, sex, location."

"There are some people who are totally innocent, looking to chat. We will chat with those individuals, and I would say nine out of 10 individuals who contact us will chat with us and say 'You're too young, be careful,"' he said. "That's what we like to see."

Others are more persistent.

"Wsup," he messages back to one.

In just a few minutes, an instant-message chat can go from friendly to explicit.

"This guy's asking, 'Can I suck on your boobs?"' McQuiston said.

In another window, a man has just sent him a picture of his genitals.

"U like my pic?" he writes.

McQuiston writes like a teenager, something that involves a lot of research.