SAN DIEGO -- A 27-year-old former Clairemont High School history teacher pleaded guilty Wednesday to having unlawful sexual intercourse with one of her male students two years ago and plying him with cocaine and alcohol.

Danielle Marie Walls faces a sentence ranging from probation to 5 1/2 years in state prison when she is sentenced Sept. 26 by San Diego Superior Court Judge Frank Brown.

The former teacher, who admitted having sex with the 16-year-old on four occasions between April and June 2004, also pleaded guilty to a misdemeanor charge of contributing to the delinquency of a minor by encouraging him to use drugs and alcohol.

"The sad thing is you had a bright future. That's gone," the judge told the defendant, who remains free on $65,000 bail pending sentencing.

But Brown commended Walls for admitting guilt at an early stage to avoid putting the victim and his family -- who reported her to police -- through any further ordeal.

Outside court, Deputy District Attorney Dwayne Moring said he will review the facts of the case and psychological reports on the ex-teacher before deciding whether to argue for prison time.

"The defendant violated a trust," the prosecutor said.

He said the victim, now 18, has been ridiculed and has suffered psychological damage as a result of Walls' actions, including providing him with drugs and alcohol.

"That was a monumental mistake on her behalf," Moring said.

The victim was in Walls' 10th-grade history class in 2004, a time when the defendant was an "out-of-control cocaine fiend," Moring said earlier.

Although Walls admitted to four sexual encounters, the prosecutor earlier said that she had sex with the boy 10 to 25 times over several months.

They engaged in sex acts in at least four hotels between April 2004 and the end of that summer, according to Moring.

The evidence in the case included hotel and credit card receipts, cell phone records, statements from the victim and several other students and text messages that were sent during "all hours of the day," he said.

Moring said the defendant gave the victim cocaine on one occasion and tried to give him more another time.

Under her plea deal, Wall pleaded guilty to five out of 16 counts. She could have faced up to 16 years behind bars if convicted as charged.

Walls told the judge at her arraignment in June that she had been working as a real estate agent since resigning her teaching post a year ago.

She did not make a statement upon entering her plea, nor did she speak to reporters outside the courtroom.