COMPTON, Calif. — A teenage girl was convicted today of two counts of first-degree murder for her role in the killings of her mother and stepfather in the family’s Compton mobile home.

Jurors deliberated for about four hours before reaching a verdict in the trial of Cynthia Alvarez, 16.

The panel also found true special circumstance allegations of lying in wait and multiple murders. Alvarez is not eligible for a death sentence because of her age, but she faces 51 years to life in prison when she is sentenced June 21.

In closing arguments that wrapped up Thursday, Deputy District Attorney Kristin Trutanich told the Compton Superior Court jury the evidence against Cynthia Alvarez was “overwhelming.”

Alvarez’s attorney, Carole Telfer, insisted her client was not guilty of the charges, saying, “She did not commit two brutal murders.”

Jurors began deliberating Friday afternoon and resumed this morning, announcing just before noon that they had reached a verdict.

Trutanich told jurors the defendant is a murderer who conspired with her boyfriend to kill her parents.

“Cynthia Alvarez, at 15 and a half years old, had a boyfriend for over a year named Giovanni Gallardo, and the two of them planned, executed the murders of her parents on October 11th, 2011,” the prosecutor told jurors hearing the case against Alvarez, who will turn 17 next month.

Gallardo, who was 16 at the time and is now 18, is scheduled to go on trial Monday in connection with the killings of Alvarez’s mother, Gloria Villalta, 58, and her stepfather, Jose Lara, 51.

Telfer on Thursday described the defendant as having been “consistently abused in her life,” whipped with belts, but said she still loved her mother.

She said her client was forced by her mother to lie when the Department of Children and Family Services investigated a report that her stepfather had sexually assaulted her.

“Her life has been lived in a nightmare and she’s handled it pretty well,” Alvarez’s attorney told jurors, saying her client, who has a language processing disorder, needs to be “saved.”

The prosecutor countered that Alvarez’s conduct at the time of the killings showed her mental state was “to get rid of her parents.”

Villalta’s decomposed body was discovered in a shallow grave at a vacant lot in Norwalk, while Lara’s body was found at a vacant lot in Long Beach.

Alvarez testified in her own defense during the trial, insisting she did not take part in the killings, which she said were carried out by Gallardo.

She admitted hitting her stepfather with a bat but said it was only because she feared Gallardo would hurt her if she didn’t comply with his orders.

The teenager acknowledged that she and Gallardo went shopping for party supplies while her mother’s body was in the back of the vehicle they were using.

Trutanich told jurors, “It’s absolutely disturbing what she did to her parents, the way she let them die and then rot — one in the car, one in the ground.”

Alvarez’s role was as an “aider and abettor, at least to her mother’s murder,” Trutanich said.

After Alvarez’s mother was strangled and her body was dragged into a storage room, Alvarez did nothing to stop her boyfriend as he prepared to swing at her stepfather with a baseball bat as he walked into an “ambush” in the mobile home, Trutanich said.

During the attack, Alvarez hit her stepfather with the bat and handed Gallardo a knife “to let Giovanni finish him off” by stabbing him 11 times, according to the prosecutor.