An Olney teenager pleaded guilty yesterday to participating in a Gaithersburg home invasion that left one teenager fatally shot and another stabbed--all because she and two friends wanted to recoup $60 they had spent on fake cocaine.

Shiva Dayani, 17, broke into tears and sniffled as she repeatedly answered "guilty" when Montgomery Circuit Court Judge Paul H. Weinstein asked how she pleaded to each of 15 charges, including second-degree murder, attempted second-degree murder and armed robbery.

Dayani, who was accused of stabbing one teenager and binding the wrists and ankles of five teenagers in the house with duct tape, could face 65 to 115 years in prison, according to Maryland sentencing recommendations, prosecutors said. She was convicted as an adult and is scheduled to be sentenced Sept. 22.

Prosecutors told Weinstein that Dayani's co-defendants, Joshua Friedman and Chelsa Sommer, both 19, have agreed to plead guilty to the same charges.

Dayani's attorneys, Paul Stein and Debra Grimes, said the plea saved their client from a possible life sentence had a jury convicted her of felony murder for participating in the robbery that ended with the death of Ali Rabonik, 18, from a shotgun blast to the face.

The statement of facts provided yesterday by prosecutors as part of the plea was the most detailed account to date of the events that led to Rabonik's death.

Prosecutors said Dayani and her two friends drove to the two-story house in the 8100 block of Brucar Court, a quiet street in the Washington Grove section of Gaithersburg, the night of Jan. 11 to rob the teenagers living there. They had bought marijuana, heroin, cocaine and Ketamine--a cat tranquilizer that was Dayani's favorite hallucinogenic--from the house for two months, prosecutors said.

The homeowner had moved out a few months earlier and had left his two sons, ages 18 and 22, living there alone. Soon other teenagers moved in, and the home became a "party house" where young people in the heart of Montgomery County suburbia drifted in and out to sell, buy and use drugs, said Assistant State's Attorney Peter Feeney.

But Dayani complained that some heroin she had bought there made her violently ill, Feeney said. And $60 worth of cocaine she also had purchased there turned out to be heavily diluted with another white powder.

While Sommer waited outside the Brucar Court home as the getaway driver, Dayani and Friedman entered through the unlocked front door, Feeney said. The first floor was dark.

"This is perfect," Dayani told Friedman, according to her statement to police. "They don't know we're here."

The two went upstairs, with Dayani carrying a hunting knife and silver duct tape in the pockets of her red fleece sweat shirt, a .32-caliber revolver tucked up one sleeve, and Friedman hiding a shotgun under his coat. In a bedroom, they found Jamil Numan, Rabonik and a teenage girl. Two other teenagers, apparently unaware of the robbery taking place inside, entered the bedroom shortly after, Feeney said.

Dayani pointed the handgun at Numan, ordered him to give her cocaine and then taped the teenagers' wrists and ankles with duct tape. Another young man who lived in the home overheard the commotion and fought with Friedman for the shotgun. Numan, who had broken free from the duct tape, also fought with Friedman, prosecutors said.

With Friedman in a fight, Dayani used both hands to plunge the five-inch knife into Numan's back and was about to stab him in the chest when Rabonik broke free of his constraints and tackled her, prosecutors said.

During the struggle over the shotgun, Friedman said, "It's loaded!" Then the gun discharged, hitting Rabonik in the face, prosecutors said.

Feeney said Dayani told police that they had "planned to get their money back. There was no plan to hurt anyone or shoot anyone."