Fairfax County jurors who began deliberating Wednesday in the murder trial of a woman who tossed her 2-year-old granddaughter off a mall walkway are faced with a single question: Was she sane at the time?

Prosecutors and defense attorneys agree that one evening last November, Carmela dela Rosa was on a family outing at Tysons Corner Center when she scooped up 2-year-old Angelyn Ogdoc and threw the little girl off a 44-foot walkway to her death.

But during a seven-day trial that included testimony from dozens of witnesses, the two sides presented starkly different portraits of the 50-year-old grandmother and her mental state at the time of the incident.

Prosecutors said Dela Rosa was jealous of the attention Angelyn received and she wanted to exact revenge on the girl’s father, whom Dela Rosa blamed for getting her daughter pregnant out of wedlock.

“She was basically angry at the world and her place in it,” Commonwealth’s Attorney Ray Morrogh said in his closing statement. “And unfortunately for this child . . . she decided to take her anger out on her.”

But Deputy Public Defender Dawn Butorac described Dela Rosa as a devoted grandmother who was sent into a “downward spiral” by mental illness in the months before Angelyn’s killing. Butorac said Dela Rosa, who entered a plea of not guilty by reason of insanity, could not distinguish right from wrong the chilly night of Nov. 29, 2010.

“These things got into her head and got jumbled up,” Butorac said. “They became psychotic thoughts.”

During her closing argument, Butorac stressed Dela Rosa’s better days, showing jurors pictures of the grandmother hugging Angelyn and holding her when she was a baby.

Kathlyn Ogdoc, Dela Rosa’s daughter and Angelyn’s mother, sat in the front row of the courtroom with husband James Ogdoc. They cried quietly.

The jury will decide whether Dela Rosa is guilty of first- or second-degree murder or not guilty by reason of insanity. If convicted, she could face a sentence of up to life in prison.

Key testimony came in the final days, when the prosecution and defense each called psychologists who presented different conclusions about Dela Rosa’s mental state.

Stanton Samenow, a clinical psychologist who testified for the prosecution, said Dela Rosa was “devastated” when Kathlyn got pregnant at 19 before she was married, and Dela Rosa never got over that fact. The night she learned her daughter was going to have a baby, she locked herself in her room and said the rosary. She focused her rage on James Ogdoc.

“There is a lot of hate in this woman,” Samenow said.

When asked whether Dela Rosa was suffering from psychosis, Samenow was succinct: “Absolutely not,” he said.

Instead, Samenow testified that Dela Rosa has a borderline personality disorder. Dela Rosa was “angry, uncompromising, unforgiving and difficult” and had alienated members of her family, Samenow testified.

On Tuesday, clinical psychologist Michael Hendricks testified for the defense, saying Dela Rosa suffered from a major depressive disorder with psychotic features that clouded her thinking so much she was legally insane that day. Dela Rosa had battled mental illness since 2001, after her father died.

Hendricks testified that the bout of depression that gripped Dela Rosa beginning in summer 2010 was “considerably worse” than any she had experienced before. Dela Rosa tried to commit suicide by slashing her wrists, swallowing pills and sending her minivan careening over the side of Skyline Drive near Front Royal.

Earlier in the trial, the defense called Dela Rosa’s friends and relatives, who testified that the grandmother had been trying to organize a family reunion and called Angelyn by the nickname “Lovey.”

The testimony was a jarring contrast with a videotaped interview between Dela Rosa and Fairfax County detectives played in court. The grandmother admitted to killing Angelyn.

“I just saw James through her, through the baby,” Dela Rosa said in the interview. “I thought about James and I threw her.”

In his closing argument, Morrogh said Dela Rosa hatched the plot to kill Angelyn minutes before leaving the mall.

He said images from a surveillance camera show that Dela Rosa let her family pass, then darted to the railing with Angelyn.

Early in the trial, Kathlyn Ogdoc testified about that moment of horror.

She said she glanced back at Dela Rosa and noticed she was no longer holding Angelyn.

“Her hands were over” the railing, Ogdoc said, crying. “I said, ‘What just happened?’ ”