American University freshman Kenneth Alicea had only been on campus long enough to hang airplane posters in his room and make a few acquaintances. Alicea died late Saturday night after a two-story fall from his dormitory, three days before his first class.

According to police and campus officials, the 18-year-old crawled through the screenless jalousie windows of his dorm room and onto the roof of a small wing at the rear of the building.

If he had moved to his left, they said, there would have been plenty of room to walk. Alicea moved to his right, apparently by accident, according to police, and stepped off the roof. He fell, headfirst, about 25 feet to the concrete pavement in front of a rear entrance at about 10 p.m. He died about an hour later at Georgetown University Hospital.

"In the brief time that I knew him, I can tell you that he was a great guy. He was really easygoing, really affable," said one shocked freshman who lives two doors down from Alicea's room at Letts Hall. "It's a terrible, terrible thing."

Authorities, who are handling the case as an accidental death, said that there was no indication that Alicea was despondent about anything.

"He was not attending any party. He was in his room with a few friends," said Paul W. Leeper Jr., chief of security at the university.

"We've never had anything like this happen before, never an accidental death like this," Leeper said.

Alicea's parents, who live in the Bronx, were here yesterday to meet with the president of the university and authorities. They were unavailable for comment.

On the AU campus, particularly the Letts-Anderson dormitory quad, there was little indication of the tragedy that had occurred the night before. A stereo blared, "Say do you remember dancing in September? Never was a cloudy day," as some parents continued to help their children move in and unpack.

Those who had heard of Alicea's death knew too little about him to be really despondent. Others had not heard at all. Yesterday was a time to find friends from the year before, to wonder who the new female student was who had her own Mercedes, to settle into the first time freedoms of being a freshman away from home.

Sophomore Dan Alper remembered: "It's a period of adjusting and for certain people who are new, they adjust by partying, breaking loose, getting used to their freedom. It seems like something unfortunate always happens at the beginning of the school year," he said.

Anna Stein, a freshman from Montreal, said, "That's terrible. I don't stay on campus at night. If there's a party it's not really a party, just a drinking session. I haven't been here one night because of that."

One of the students who lived near Alicea said he was "always talking about the Bronx, what a hassle it was to live there. He was very friendly, laid back."

Joseph Meyerson, a freshman from Great Neck, N.Y., said he was briefly in the room with Alicea. "There were just some friends of his having a good time. Then one of them was running down the hall looking for the resident adviser. Somebody had fallen off the roof ," Meyerson said.

One parent of an incoming freshman who asked not to be named put it this way. "You always wonder, 'Are they going to be able to handle it here?' But you can't hold their hands for four years. You have to be willing to trust and let go."