The former Gallaudet University student who collapsed Friday after a "grade dispute" with an instructor and a struggle with campus security officers died of asphyxiation, according to an autopsy, D.C. police said yesterday.

Police said that the death of Carl Dupree, 41, of Springfield, has been ruled a homicide, meaning that his death was caused by another person.

The case is being referred to the U.S. Attorney's Office. Spokeswoman Judy Smith would not speculate on what will happen when the office receives the case.

Dupree died shortly after he was restrained by at least five campus security officers in the Hall Memorial Building at Gallaudet, the campus in Northeast Washington that houses the nation's premier university for deaf students.

Dupree had gone to see an English instructor, and an argument ensued. The security officers were summoned by the instructor, who has not been identified by the university. University officials said that the officers encouraged Dupree, who was deaf, to leave. When he did not leave, they cuffed his hands behind his back, officials said.

After Dupree collapsed, he was taken by ambulance to Capitol Hill Hospital, where he died.

Since Dupree's death, some students have criticized the actions of the security officers, complaining that they had used excessive force and had, in effect, silenced Dupree by cuffing the hands he used to communicate.

A university-financed probe of the incident got underway yesterday.

The university, which employs about 25 security officers, looks for candidates with three years of law enforcement experience, a spokeswoman said. New hires go through a "pretty comprehensive," seven-week campus security officer training program, the spokeswoman said.

Employees are expected to learn sign language, and supervisors are expected to "have a higher level of proficiency," she said. Another official said "some of the guards are quite fluent; others are not."

Dupree's sister, Sue Johnson of Woodstock, Ga., said the family was "just devastated by the whole matter."

Johnson is here with her brother's family, "trying to keep his wife calm, and my mother, and his children, ages 4 to 11; they don't understand why he is dead, and we are trying to explain."

Carl Dupree was a student at Gallaudet years ago, and enrolled again last September. But he withdrew from his studies about three weeks ago, university officials said.

At Gallaudet, Dupree was active in a student movement that has been protesting the university policy that requires new students to complete a basic English course known as English 50. Students have four semesters to pass the course. If they don't, they can be barred from continuing at Gallaudet. It was unclear whether the argument that occurred before Dupree's death had to do with English 50.

"Last spring there was some rallying, and Carl Dupree identified himself as a leader of that group," said Christine Multra, president of the Gallaudet student government.

Multra said that the student government has been meeting for months with faculty members to resolve the disagreement over the English issue, which is part of a larger debate at Gallaudet over English requirements and the use of sign language in the classroom.

Dupree's death has focused attention on the English controversy as well as another long-smoldering issue: the need for teachers, administrators, and now security officers, to be fluent in sign language to communicate with students, Multra said.

The mood on the campus this week has been somber, and some students have boycotted classes out of concern for what happened to Dupree.

"Overall attendance is down," said Robert Williams, dean of the School of Arts and Sciences. He said he has encouraged his faculty to be "understanding and flexible with students who are in mourning."

Individual instructors were free to cancel their classes, Williams said. Other instructors held classes but did not take attendance.

"People are very upset about what happened," Williams said. "They want to know more details, exactly what happened, why it happened."

Working to do that is Scott Kragie, a lawyer with the law firm, Squire, Sanders and Dempsey, who has been retained by Gallaudet president I. King Jordan to conduct a review of Dupree's death.

"I can't go into details," Kragie said, "but we will interview people, go to the logical sources."