Charles Curtis, a Martinsburg, W.Va., man charged with murdering Judith L. DeMaria near a popular regional bicycle path in August 1985, yesterday pleaded guilty in Loudoun County Circuit Court to the slaying.

What had been expected to be a long, tedious jury trial before a plea arrangement was reached last week ended in 10 solemn minutes in a half-filled courtroom.

There was silence as Curtis muttered "guilty," first to a charge of abduction with intent to defile, then to first-degree murder. But as he was rushed out of the courtroom, someone in the background called out, "Murderer."

The disappearance of DeMaria, 27, a tennis and racquetball instructor, had baffled police for more than two years when Curtis stepped forward and led officials to DeMaria's body. Curtis, 28, is described by police as a drifter.

Prosecutors dropped a charge of attempted rape, but Curtis faces possible life sentences on both the murder and abduction charges. Loudoun County Circuit Judge Thomas Horne set sentencing for May 5.

Curtis told deputies that he used a razor knife to slash the throat and wrists of DeMaria, who was seen jogging along the Washington & Old Dominion bicycle trail late in the morning of Aug. 2, 1985, the last day she was seen alive.

The next day, police found a pool of blood in a field near a section of the bicycle trail in Sterling. That was the last evidence police found. In September 1987, Curtis walked into a Sterling police substation and began talking about DeMaria's disappearance, according to law enforcement officials.

Documents recently placed in court files reveal more than was publicly known about Curtis' account of the events that led to DeMaria's death.

A day after his arrest, Curtis made a detailed map showing where and how the murder took place, according to court records. Curtis had told police that he had planned to rape DeMaria and that he began to stalk her as she jogged on the trail. Curtis wrote on his map that he saw DeMaria at least three times on the trail. He also indicated on the map where she was attacked.

"This map shows an ugly drug-related crazy trail that took the life of Judy Demirera {sic}," Curtis wrote on the map on Sept. 11.

"May she rest in peace with God and may her family know I have shown remorse many times in the 2 years i kept it fogged in a drug filled mind."

John DeMaria, the victim's father, said yesterday that he did not doubt Curtis' remorse.

"He would have to be inhuman not to have feelings of guilt," said DeMaria, 60. "It's a pretty complex time for me. There are a lot of conflicting emotions. Personally I have had a difficult time feeling anger toward Curtis. People knowledgeable of this sort of thing say maybe I should feel anger in order to cope."

His daughter's death raises questions about a society that seems to "foster that the male animal can abuse females," DeMaria said.

"I've got two granddaughters and I worry about them. I see girls out on these trails and I worry."

Loudoun Commonwealth's Attorney William T. Burch, who said that he would ask that the life sentences run concurrently, said he knows of only one reason Curtis might have come forward. "You never know what motivates somone, other than the two years of thinking about it," he said.

In a letter to a girlfriend after he was jailed, Curtis wrote, "Judy Demiria {sic} thought I was following her. But in fact that day i was going to rip off a couple of pot {marijuana} patches to sell to buy more PCP {a hallucinogenic drug}. I was ripped {high} and she confronted me about following her. An argument ensued she struck me and we had at it and I killed her."