Four hours later, three gunmen followed 24-year-old Sarhan and shot him to death blocks from his home in the capital.

The campus, already simmering with sectarian tension, exploded with violent demonstrations that continued Wednesday. Enraged Shiite students stormed the cafeteria, overturning tables and breaking windows. They accused Sunni students and professors of supporting Saddam Hussein's Baath Party, which they blamed for Sarhan's death. Police fired shots in the air to stop the riots. The dean fled the campus and classes were canceled indefinitely.

''It wasn't a demonstration - it was a riot,'' said Lina Majed, 22, a Russian studies student who was in the cafeteria during the violence. ''I won't come back to college until everything settles down. This is scary.''

Sarhan's murder was a disaster for Baghdad University officials who had been trying to quell sectarian problems among students since the January elections. Shiites and Kurds dominate Iraq's first elected government. Sunni Arabs mostly boycotted the vote or stayed away out of fear of attack from Iraq's Sunni insurgency.

Fights have since erupted on campus when Shiites assert their identity through religious posters. Sunnis, meanwhile, are sick of being labeled Baathists and insurgent sympathizers.

''Our Sunni brothers think they lost the battle, so they are trying to rip away the joy of the Shiites,'' said Alaa Mahmoud, 23, a geography student involved in the protest. ''In the old days, we feared Sunnis because they were Baathists. Now, we fear them because they might be terrorists.''

Sarhan, who was a senior in the College of Pharmacy, is a martyr to Shiite students, who considered him a pious leader striving for unity. Sunni students, however, described Sarhan as a religious extremist and said his Shiite propaganda invited trouble.

''Why are [the Shiite students] so upset? A man asked for a war and he got it,'' said a Sunni linguistics student who didn't want her name published for fear of retaliation from other students. ''If they were really good, they would demonstrate peacefully. But what they're doing is making them lose their cause.''

Sarhan, a member of the Dawa Party led by Iraqi Prime Minister Ibrahim al-Jaafari, invited students to the party Monday to celebrate Shiite self-determination after decades of oppression under the former regime. His friends said he brought loudspeakers to broadcast pro-Shiite messages, passed out candy and plastered posters of al-Jaafari across campus.

During the celebration, several students said, they noticed a man with a gun mingling with the crowd. Sarhan asked the man to identify himself, but he refused and the two got into an argument.

The man later turned out to be a bodyguard for the College of Pharmacy's dean, a Sunni Arab, according to students and accounts of the incident in Iraqi newspapers.

The fight with the bodyguard ended the party, so Sarhan loaded up his beige Peugeot and headed home. Blocks from his house, his family said, three men in a gray Opel sedan opened fire and killed him in front of a busy shopping center.