He was killed on July 20, during a clash between demonstrators and Italian Carabinieri (military police). The police were in a jeep and were engaged in a conflict with protesters; police were lobbing tear gas while demonstrators were throwing stones. Carlo Giuliani was holding a fire extinguisher and some photos ([1], [1], [1], [1]) suggest that he intended to throw it at the police jeep. Carlo Giuliani was shot in the face, and the police jeep then ran over his body. All charges against the police officer who shot him have been dropped.
The plaza where he was shot, Piazza Alimonda, was unofficially renamed "Piazza Carlo Giuliani" by activists, who erected a memorial there for mementos, photographs, writings and flowers. This memorial has since been burned twice by unknown vandals. Another plaza, in Bern, Switzerland, has also been named "Carlo-Giuliani Platz" in memoriam; the renaming took place during a memorial art exhibition called The Geometries of Memory.
Although countless people, demonstrators included, have been killed and continue to be killed by police around the world, Carlo Giuliani is often held up as a martyr for what is commonly called the Anti-Globalization Movement.
Carlo Giuliani had been member of a punk group called "Beast Punks". He had been living in Genoa and employed at the Centro Social Nordeste.