Prescott Sigmund, the former Potomac insurance salesman who eluded authorities for four months while living in a college town in Montana, pleaded not guilty yesterday to charges in the July 12 pipe bombing in Washington that critically injured his half brother.

Yesterday's hearing in a federal courtroom in downtown Washington was Sigmund's first public appearance in the area since he vanished in mid-July. He had been working as a desk clerk at the Comfort Inn in Missoula, Mont., using the name Paul Nott. The 35-year-old fugitive, who left behind a wife and two young children in Potomac, surrendered to Missoula police Nov. 9 after seeing his case featured on the Fox television show "America's Most Wanted."

Clad in an orange prison jumpsuit and still sporting the beard he grew while living in Montana, Sigmund stood in the courtroom next to his court-appointed attorney, speaking in hushed tones. Authorities said it did not appear that any family members were present.

U.S. Magistrate Judge Alan Kay told Sigmund that he qualified for a court-appointed attorney after Sigmund informed the judge that he had no money and no bank accounts. He said that he and his wife jointly own a condominium and a 2000 Ford Explorer but that the money owed on it exceeds the value of the vehicle.

Kay granted a request by the prosecution that Sigmund remain at the D.C. jail until a detention and preliminary hearing tomorrow, when the judge will consider whether to grant bail. Assistant U.S. Attorney Jeanne Hauch had recommended that Sigmund be detained until tomorrow's hearing based on the violent nature of the crime and his disappearance in July.

Sigmund is charged with interstate transportation of an explosive device with intent to injure an individual. The maximum penalty is 20 years in prison and a $250,000 fine.

His half brother, Wright Sigmund, 21, was critically injured when he got into their father's Chevrolet Blazer in a parking garage on Wisconsin Avenue NW in the Friendship Heights shopping district.

Authorities have said that two pipe bombs with extra shrapnel were detonated when Wright Sigmund got behind the wheel. He was running an errand for his father, Donald Sigmund, 65, an insurance executive whom authorities believe was the intended target.

On July 15, three days after the bombing, Sigmund's wife, Bradey, reported her husband missing. Authorities searched the Sigmund home and found some copper wire that matched the wire used in the pipe bombs, according to a court affidavit. Investigators also linked Sigmund to wood matches used to detonate the bombs, the affidavit said.

The affidavit suggested that Prescott Sigmund faced financial problems and had hoped to benefit financially from his father's death.

Prescott Sigmund, 35, was assigned an attorney after telling the judge that he has no money.