The Justice Department has opened a civil rights investigation into the July death of an African American teenager who was killed in a brawl at a party attended by current and former students from an Anne Arundel County high school, officials said yesterday.

The county chapter of the NAACP and Sen. Barbara A. Mikulski (D-Md.) called in August for federal authorities to investigate the death of 17-year-old Jamahl Jones, citing what the NAACP called "racial overtones" to the brawl.

For many, the racial passions inflamed by Jones's death were further aggravated by the unusual course of the investigation: Four white men, ages 18 to 20, were initially charged with murder but were soon released.

A spokesman for the FBI in Baltimore, Barry Maddox, said yesterday that a preliminary inquiry began last week. He said the investigation's findings would be reported to Maryland U.S. Attorney Thomas M. DiBiagio and the Justice Department's civil rights division.

"I'm glad to see it," Rene C. Swafford, an attorney for Jones's family, said of the inquiry. "I'm hoping with the federal investigation that all of this will be over sooner rather than later with somebody having to pay the price for Jamahl's death."

Meanwhile, a white, wooden cross that was part of a roadside memorial to Jones was burned early Friday morning. Police summoned to the scene, across the road from where the fight took place, found the cross charred, a police report says. The cross, which had been surrounded by candles and other mementos, has been replaced, a neighbor said.

"It was just a total desecration," said Barbara Eckert, who lives next to the empty lot where the memorial stands. "This thing will never be laid to rest. This poor mother has to endure not just the loss of her child but somebody desecrating what she considered a memorial to her child."

On July 24, police were dispatched to a home in Pasadena for a report of a large fight. Jones was taken to a hospital and pronounced dead. Two of his friends, both of whom are black, were injured.

According to Jones's family, the three had received a call from another friend who said he had been threatened by a group of about a dozen former Northeast High School students at the party. Jones and his friends arrived, and a fight ensued.

The details of which side was the aggressor remain in dispute. Jones's friends have said they believe that he was targeted because of interracial dating.

Detectives soon charged Joshua D. Bradley and David M. George, both 20, and Jacob T. Fortney and Richard E. McLeod, both 18, with first-degree murder.

Anne Arundel County State's Attorney Frank R. Weathersbee withdrew the charges less than a month later, saying the findings of a preliminary autopsy report were inconsistent with the initial police assessment. Weathersbee said yesterday that he does not expect the federal inquiry to affect his ongoing grand jury investigation into the case.

"Certainly, tandem investigations can go on and have indeed gone on," Weathersbee said. "If they want to see anything the Anne Arundel police have done or we've done, I'm happy to show it to them."

David Putzi, an attorney for Fortney, predicted that the federal investigation would clear his client. "They are going to uncover what everyone else already knows is true, specifically that race was not an issue in this incident," he said. Of the cross burning, Putzi said, "Obviously I think that's just repugnant, if that's in fact what occurred."