A man walked into a Science Center exam room and threatened to set off a bomb yesterday morning, before students fled and police took him into custody. No one was harmed in the incident. The man did not have a bomb.

The man, who police said identified himself as Kenneth E. Leong, 21, pled not guilty to charges of making a false bomb threat, disorderly conduct and trespassing at his arraignment yesterday. He was committed to a hospital for a 20-day mental evaluation after an evaluation by a court psychiatrist.

The man interrupted the final exam of Literature and Arts B-21: "Images of Alexander the Great," in Science Center B at around 9:40 a.m. About 250 students--half the class--were in the room.

Loeb Professor of Classical Art and Archaeology David G. Mitten, the course professor, described the man as tall and thin, with facial hair, a dark complexion and dark clothes. He said the man looked "extremely agitated."

As the exam was just beginning with several slide identifications, the man threw a brick at the blackboard and, after whipping off a satchel he had slung around his neck, informed the room that he had a bomb and "would kill everyone."

Mitten demanded "Who are you? There's an exam going on." The man replied that his name was "Romanticist" and that if anyone tried to leave the room he would detonate his bomb. He said he was "declaring war on the United States of America."

Mitten said his first thought was that the man was a student late for an exam, but then, "I realized he was dead serious and this was real trouble."

The man told the students to put their heads down on their desks, but one student jumped up and ran out, starting a "stampede" for the door, according to Brandan A. Kramer '01, a student in the exam room. (Science Center B housed students in the course with last names from A to P.)