A black man from Mississippi charged in Louisiana with sending racist death threats over the Internet to three black college students could face additional charges in other jurisdictions, a federal prosecutor said Monday.

Dyron Hart, 19, of Poplarville, Miss., appeared Monday before U.S. Magistrate Louis Moore, Jr., but did not enter a plea. Moore set Hart’s bond at $10,000 and ordered him to refrain from contacting his alleged victims.

“I want you to know that this is serious,” Moore warned Hart, who was flanked by his mother.

Hart is charged with using a fake profile on the Facebook social networking Web site to send threatening messages to three black students at Nicholls State University in Thibodaux.

Hart allegedly told an investigator that he was trying to “create a reaction.”

Moore appointed a public defender for Hart, who faces up to five years in prison and a $250,000 fine if convicted.

Assistant U.S. Attorney Marvin Opotowsky said Hart could face additional charges in four other jurisdictions. A date for his arraignment in New Orleans hasn’t been set.

Investigators traced the threatening messages to Hart’s home computer. He also allegedly sent threatening messages to students at LSU, the University of Mississippi and the University of Alabama, investigators said.

Hart, an unemployed construction worker, was a student at Nicholls State for the spring 2008 semester and practiced with the football team for two weeks before he left the school. Authorities say he was pretending to be a white man upset by Barack Obama’s election when he threatened to kill the students.

Opotowsky said Hart has a theft conviction on his criminal record but doesn’t have a history of violence.