MILAN  The metal shutters are closed at Shining Bar, a coffee shop near the central train station here. On the facade, someone has written “proud to be black” and spray-painted “Abba Lives” in red.

Abba was the nickname of Abdul William Guibre, who was born in Burkina Faso, raised in Italy and beaten to death here last month by the bar’s father-and-son proprietors. The two, Fausto and Daniele Cristofoli, suspected Mr. Guibre, 19, of stealing money and set upon him with a metal rod, the authorities said, when it was later determined he had stolen a package of cookies. During the altercation, the attackers shouted “dirty black,” lawyers for both sides said.

Although there is some debate about whether the killing was racially motivated, the attack on Mr. Guibre was the most severe in a recent spate of violence against immigrants across Italy. The attacks are fueling a national conversation about racism and tolerance in a country that has only recently transformed itself from a nation of emigrants into a prime destination for immigrants.

“A black English person, or French person, or Dutch person, that’s O.K.,” said Giovanni Giulio Valtolina, a psychologist and scholar at the ISMU Foundation in Milan, which studies multiethnic societies. “But a black Italian is a very new thing.”