(SANFORD, Fla.) -- In Detroit, far from the Florida town where black teenager Trayvon Martin was shot and killed, drivers were shocked to see an electronic highway sign with the word "Trayvon" followed by a racial slur.
The sign's offensive message Sunday night was quickly taken down, but it was the latest incident in which racists, neo-Nazis or white supremacists have used the controversial case as a rallying point.
Martin, 17, was unarmed when he was shot by George Zimmerman, 28, a white Hispanic neighborhood watch captain.
The shooting has spawned outrage in the black community, with protests and demands that Zimmerman be arrested for murder.
But Zimmerman claims the shooting had nothing to do with race, and that he shot Martin in self defense after the teenager knocked him down, slammed his head into the ground and went for Zimmerman's gun.
In the weeks after the shooting, outraged supporters of the Martin family held rallies and protests demanding that Zimmerman be arrested. Electronic roadside signs had been used throughout Central Florida to alert people to the rallies.
And the New Black Panther Party offered a $10,000 bounty for Zimmerman.
A backlash has been growing, though, with distinct racist undertones.
At Ohio State University last week, the words "Long Live Zimmerman" were scrawled across the side of the Frank W. Hale Jr. Black Cultural Center, a part of the university's Office of Diversity and Inclusion.
"It's a hate crime," Larry Williamson Jr., director of the Hale center, told ABC News. "Some people see it as just graffiti but if you see something done in such a negative way, you're going to have a community that feels hate."
In Sanford, Fla., where the shooting took place, the specter of racism is ubiquitous. A group of armed neo-Nazis from the National Socialist Movement have descended upon the town, touting their intention to patrol the town to protect whites against a race riot.
The Rev. Terry Jones, the controversial pastor who once threatened to burn copies of the Koran, announced last week his plan to hold a rally on April 21 at the Seminole County Courthouse in support of Zimmerman and his constitutional rights.
And reporters covering the emotionally charged story have been inundated with angry tweets and social media messages, with some of the messages verging on threats.
Capt. Robert O'Connor of the Sanford Police Department told ABC News, "Law enforcement agencies in the area are monitoring a variety of activities and groups to ensure that conditions remain peaceful."
Copyright 2012 ABC News Radio