Charles Curtis, a drifter accused of brutally murdering Judith L. DeMaria near a Loudoun County bicycle path in August 1985, has decided to plead guilty to the slaying, preempting a jury trial scheduled to begin tomorrow, according to the defense attorney and prosecutor.

Blair Howard, Curtis' attorney, and Loudoun County Commonwealth's Attorney William T. Burch said they agreed Friday that Curtis will plead guilty to first-degree murder and abduction with intent to defile, and that the prosecution will drop a charge of attempted rape.

Curtis, 28, who faces life imprisonment on both the murder and abduction charges, is expected to enter his plea formally before Circuit Judge Thomas Horne at a 9:30 a.m. hearing tomorrow.

The plea culminates a widely publicized murder mystery that began Aug. 2, 1985, when Judith DeMaria, 27, a popular tennis and racquetball instructor, failed to return from a late morning jog on the Washington & Old Dominion bicycle trail.

One day after her disappearance, deputies discovered what they described as a "substantial amount of blood" in a field near the path.

Authorities were unable to find DeMaria's body and were stymied in their investigation until Curtis walked into a police substation Sept. 9 and volunteered information about the case.

A few hours later, police found DeMaria's badly decomposed remains in a shallow grave in a wooded area not far from where she was last seen.

Deputies said Curtis, who led them to the grave, at first said someone else killed DeMaria, but later said that he had stalked her, and then slashed her wrists and throat with a razor knife similar to that used to cut carpets.

Howard described Curtis as a "troubled young man" whose conscience eventually wore him down. "I am absolutely certain that his reason for coming forth when he did was the result of the torture he had been going through," Howard said, adding that Curtis had not been a prime suspect in the case.

Howard said he believed the plea arrangement was "fair."

Burch said only that the deal had been consummated and that he planned to seek life terms on the murder and abduction charges.

Friday's agreement came shortly after Horne ruled as admissible evidence videotaped statements Curtis made to police in which he admitted killing DeMaria.

Howard recently filed pretrial motions to suppress his client's statements, saying police violated Curtis' constitutional right to due process when they failed to read him his rights at the appropriate time.

Horner agreed that police should have read Curtis the Miranda warning before taking his first admission of guilt, but held that the taped statements were admissible because Curtis signed a document waiving his right to remain silent, Howard said.

The prosecution said its case was to be based primarily on Curtis' statements because the Northern Virginia Medical Examiner's Office was unable to determine the cause of death or whether DeMaria had been raped.

Curtis' statements to police gave an account of a man, high on drugs, who lost control of himself.

"My first intention was to rape the girl, but I didn't," Curtis told deputies, according to court records. "But then again, I got to thinking that I had gone that far, she could identify me as being her rapist, you know if I did rape her . . . so I took the razor knife out of my back pocket. I cut her throat . . . . First I tried to cut her wrists . . . . And I will say that I was all messed up on drugs and stuff that day."

"Lord knows he {Curtis} cooperated," Howard said.