COLUMBUS, Ohio (AP) -- Officials say graffiti spray painted on the wall of a black cultural center at Ohio State University likely stems from the nationwide unrest over the fatal shooting of a black Florida teenager.

The graffiti painted early Thursday said "Long Live Zimmerman." Columbus media outlets report that officials believe it's a reference to George Zimmerman, the neighborhood-watch captain accused of killing 17-year-old Trayvon Martin in Sanford, Fla., in February.

Ohio State President E. Gordon Gee says university police are "vigorously investigating." The graffiti has been removed.

It was discovered the same day a campus rally was held for Martin and Shaima Alawadi, an Iraqi woman who was fatally beaten last month in her El Cajon, Calif., home

Zimmerman is white and Hispanic. His family insists he's not racist.