IT SEEMED BOTH UNLIKELY and peculiar, but a respected assistant professor of English at Dartmouth was the subject of the FBI surveillance in New Hampshire. He had recently gone into a chat room called Taboo and bragged about an exclusive Web site where anything could be bought, if you had enough money.

An agent at SIOC had downloaded the strange conversation with Mr. Potter . . .

Boyfriend: Exactly how much is enough money to buy “anything”?

Mr. Potter: More than you have, my friend. Anyway, there’s an eye scan to keep out riffraff like yourself.

The Package: We’re honored that you’re slumming with us tonight.

Mr. Potter: The Wolf’s Den is only open about two hours a week. None of you are invited, of course.

It turned out that Mr. Potter was the moniker used by Dr. Homer Taylor. Guilty or not, Dr. Taylor was under a microscope right now. Twenty-four agents in two-person teams working eight-hour shifts were watching every step he took in Hanover. During the work week, he lived in a small Victorian house near the college and walked back and forth to classes. He was a thin, balding, proper-looking man who wore English-made suits with bright-colored bow ties and purposefully uncoordinated suspenders. He always looked very pleased with himself. We’d learned from college authorities that he was teaching Restoration and Elizabethan drama as well as a Shakespeare seminar that semester.

His classes were extremely popular and so was he. Dr. Taylor had the reputation of being available to students, even ones who weren’t actually taking his courses. He was also known for his quick wit and nasty sense of humor. He often played to standing room only, which he called “full houses,” and frequently acted out scenes, both the male and female parts.

It was assumed that he was gay, but no one was aware of any serious relationships the professor had. He owned a farm about fifty miles away in Webster, New Hampshire, where he spent most weekends. Occasionally, Taylor went to Boston or New York, and he’d spent several summers in Europe. There had never been an incident with a student, though some of the males called him Puck, a few to his face.

The surveillance on Taylor was difficult, given the college-town atmosphere. So far, it was believed that our agents hadn’t been spotted. But we couldn’t be certain of that. Taylor hadn’t been seen doing much beyond teaching his classes and returning home.

The second day in Hanover, I was in a surveillance car, a dark blue Crown Vic, along with an agent named Peggy Katz. Agent Katz had been raised in Lexington, Massachusetts. She was a very serious person whose main hobby seemed to be an avid interest in professional basketball. She could talk about the NBA or WNBA for hours, which she did during our surveillance time together.