Douty said he helped hide the woman's body.
Berkeley County Prosecuting Attorney Pamela-Games Neely told Berkeley County Circuit Judge David Sanders during a pretrial hearing that the slaying happened around Memorial Day last year.
Games-Neely told Sanders that Starcher's body was put in a blue, plastic-like tub and cleaning fluid was put on the body in an attempt to hide DNA evidence.
The tub was put in a car, taken to Dam #4 Road and "kicked over" into some weeds, Games-Neely said.
Starcher's body was found by West Virginia State Police on June 20.
Because of the body's condition, DNA could not be obtained from the 40-year-old Martinsburg woman to determine if it matched stains found on a couch in Juntilla's house, Games-Neely said.
"All we have is a skeleton and hair," Craig Manford, Juntilla's attorney, told Sanders.
Because authorities could not get DNA samples from Starcher's body, DNA samples were obtained from a daughter of Starcher and her father, Games-Neely said.
Through DNA tests, which Games-Neely received Monday, it was determined that Starcher's DNA might have been in three stains found in Juntilla's home and Juntilla's DNA might have been in four stains, Games-Neely said.
Because Manford has not had a chance to review the DNA test results, Sanders decided to postpone Juntilla's trial until Sept. 2.
Juntilla and Douty had been scheduled to stand trial beginning June 10.
In a plea agreement for Douty, he might be eligible for parole after serving 15 years in prison, Games-Neely said.
If Douty would have been convicted of felony murder by a jury, he could have faced life in prison without a chance for parole, Games-Neely said.
Also, Douty has agreed to testify against Juntilla, said Andy Arnold, Douty's attorney.
Juntilla sat silent while Arnold described how Douty would testify against the co-defendant.
Sanders set a sentencing date of Aug. 4 for Douty, but lawyers agreed later Monday that the sentencing would be postponed until after Juntilla's trial.
Manford asked Sanders what would happen if Douty later decides not to testify against Juntilla in Juntilla's trial.
"If he (Douty) gets cold feet, he's in trial," Games-Neely said.
In exchange for Douty pleading guilty to first-degree murder, other charges against him, including sexual assault, conspiracy to commit sexual assault, conspiracy to commit murder and a first-degree murder charge will be dropped, Games-Neely said.
The first-degree murder charge is the same charge as felony murder but it approaches the case from a different theory, Games-Neely said.
If Douty's case had gone to trial, Games-Neely said she would have had to decide which murder charge to pursue.
Juntilla faces the same charges as Douty.
In Juntilla's trial, Games-Neely said Juntilla's former girlfriend, Stefanie Brennan, is expected to testify.
Brennan was told by Juntilla that he did something like Hannibal Lecter might have done, Games-Neely said.
Lecter is a fictional character in a series of novels by author Thomas Harris. Lecter is introduced in the thriller novel "Red Dragon" as a brilliant psychiatrist and cannibalistic serial killer. He was portrayed by actor Anthony Hopkins in "The Silence of the Lambs."
Games-Neely declined to comment after Monday's hearing on a motive for the killing of Starcher.