A federal investigation was launched into the South Carolina Highway Patrol after dashboard camera videos showed a trooper using a racial slur and two others ramming their cruisers into fleeing suspects, a prosecutor said Thursday.

"I've reviewed some of the videos, and based on that review, felt that it was appropriate to have our office involved," said Kevin McDonald, acting U.S. attorney for South Carolina.

McDonald wouldn't say whether indictments could come from the investigation, which was first reported Thursday by The State newspaper of Columbia.

Highway Patrol Col. Russell Roark and his boss, Public Safety Director James Schweitzer, resigned last month after a tape surfaced showing a trooper using a racial slur in 2004.

"You better run," then-Lance Cpl. Daniel C. Campbell said to a suspect, using a derogatory term for blacks, "because I'm fixin' to kill you."

Campbell was reprimanded, suspended and ordered to undergo anger and diversity training, but Gov. Mark Sanford said Roark and Schweitzer should have fired him.