Federal prosecutors took over the witness-intimidation case yesterday against five men accused of firebombing the home of a North Baltimore community leader last month, a move that could increase the minimum penalties imposed on the defendants if they are convicted.

"Witness intimidation is a serious offense which threatens the integrity of our criminal justice system," Allen F. Loucks, the interim U.S. attorney for Maryland, said in a written statement yesterday. "We are using all available resources to combat this problem in Baltimore, including seeking the stiffest penalties possible."

The six-count indictment handed up by a federal grand jury yesterday against Andre Wilkins, 31, of Randallstown, and Jackie Brewington, 18, Richard M. Royal, 20, Isaac Smith, 25, and Nakie Harris, 29, all of Baltimore, comes as authorities continue to wrestle with witness intimidation in the city, a chronic problem that law enforcement says remains a serious obstacle to prosecuting many criminal cases.

A sixth person arrested in the Jan. 15 firebombing in the Harwood neighborhood, Antonio Newsome, was not named in the federal indictment. Although Newsome was initially identified as 18 years old, he may be a juvenile, making his prosecution in federal court more difficult, officials said. It was unclear last night how Newsome's case will be handled.

The five suspects facing federal charges remain in state custody, and no date for their first appearance in federal court has been set, a spokeswoman for the U.S. attorney's office in Baltimore said.

At least one defense attorney involved in the case criticized the decision to take the case into federal court.

"It's going to be a battleground," said Edward Smith Jr., Brewington's attorney. "In modern times, everyone wants to take cases federal."

The firebombing victim, Harwood Community Association president Edna McAbier, has not returned to her North Lorraine Avenue home. Police continue to post marked squad cars at the front and rear of her rowhouse.

According to court records, McAbier said her tires were slashed, her car was vandalized and bricks were thrown at her home's steps in the months before the firebombing. At McAbier's home, police and fire investigators found evidence of five Molotov cocktails - brown beer bottles filled with flammable fluid and with cloth wicks.

In state court, the six men were charged with 13 counts each, including attempted murder, arson and related felonies, in the attack.

In the federal indictment yesterday, five of them were charged with witness tampering, conspiracy to commit witness tampering and use of a firearm in the commission of a crime.

The penalties could be severe. Under the criminal count of witness tampering alone, the mandatory minimum penalty is 30 years in prison. The maximum sentence for the charge is life in prison.

"I'm thankful that this has been carried through and that we're seeing these indictments, because it's in the best interest of the community to have these thugs off the street," said David Wright, president of the Charles Village Community Benefits District, which includes Harwood. "I'm sad that another five men in Baltimore are in this situation, but this ... deserves strong and resolute action."

City prosecutors plan to drop their charges against the five men named in lieu of the federal indictment, said Margaret Burns, a spokeswoman for the state's attorney in Baltimore.

In another case, the local U.S. attorney's office successfully prosecuted Darrell Brooks, who set a 2002 fire that killed Angela Dawson, her husband and five of her children. The fire had been set because the Dawsons frequently called police about drug activity in their East Baltimore neighborhood. Brooks was sentenced to life in prison without possibility of parole.