Officials at the University of Pennsylvania today will complete a month-long investigation into allegations that members of a campus fraternity gang-rapped a Penn under graduate in February.

The issue has sparked the largest student demonstration at Penn in several years, and some university officials have called for a permanent ban on the fraternity.

The student, whose officials refuse to identify, has alleged that after a party at the Alpha Tax Omega fraternity house last month, she was carried by from five to eight men to an upstairs bedroom at the house and raped for more than an hour.

Fraternity members yesterday refused to comment on the investigation but have said previously that the student consented to having sex with the men.

"It was rape," Carol Tracy, director of the Penn Women's Center, said in a telephone interview yesterday. "The woman wasn't in a position to consent, as often happens after a fraternity party," she added, "and that means rape." Tracy was the first university official contacted by the student after the incident.

Tracy said the student told her she was bruised and her clothes were torn during the alleged attack.

Outraged by reports of the incident, more than 600 students gathered in Penn's main auditorium on March 10 for a "Take Back Our Lives" rally organized by student leaders and women's activists. Organizers said yesterday they called the rally to protest both the alleged rape and general violence against women, which they say has been rising steadily at Penn for the past several years.

The event, originally scheduled to last 50 minutes, created so great a response that rally organizers extended it to more than an hour and a half. Speakers included students, faculty members, and administration representatives.

"It was a very emotional thing." Liz Cooper, a former chairman of Penn's Undergraduate Assembly and one of the rally's principal student organizers, said yesterday. "I had people come up to me after the rally and say they were really moved."

A large number of fraternity members attended the rally. Bob Wilson, president of the student interfraternity council, said yesterday.

"We did not condone the event at Alpha Tau Omega and we were glad to see the rally against it," he added.

The Fraternity Sorority Advisory Board, made up of faculty, administration and three student members, today will submit its recommendations on final disciplinary action for Alpha Tau Omega to George Koval, the university's assistant vice provost for university life.

Koval, who will make the final decision on any actions to be taken against the fraternity, was unavailable for comment yesterday.