Carmela dela Rosa, her voice a halting whisper, stood in a hushed Fairfax County courtroom Friday and apologized for tossing her 2-year-old granddaughter to her death off a 44-foot-high mall walkway.

The diminutive 51-year-old wore a green prison jumpsuit and was gaunt, a shell of the woman with round cheeks from her arrest mug shot.

“I’m very sorry for what I’ve done. I’m sorry to James and Kat,” she began, referring to Angelyn Ogdoc’s parents. She apologized to her husband, mother, brother and sister, and finished with a plea as tears welled in her eyes: “I’m very sorry.”

Shortly after, Fairfax Circuit Court Judge Bruce D. White sentenced the county woman to 35 years in prison, the maximum sentence he could give. In October, dela Rosa was found guilty of first-degree murder in a case so horrific it transfixed the region.

“That a grandmother would do something like this to a granddaughter is almost incomprehensible,” White said.

As the sentence was read, dela Rosa stood with a blank look, registering no emotion. Her daughter and Angelyn’s mother, Kathlyn Ogdoc, hung her head in the front row of courtroom benches. James Ogdoc, Angelyn’s father, sat next to her with a stoic expression.

Fairfax County Commonwealth’s Attorney Raymond F. Morrogh said the young couple were so emotionally drained by testifying at the trial that they could not bear to write a victim impact statement, which is commonly submitted before sentencing. He said after the hearing that the pair drew strength from their Catholic faith but were “living in a nightmare.”

They declined to comment and did not speak at the sentencing.

On Nov. 29, 2010, dela Rosa, Kathlyn and other family members were leaving Tysons Corner Center when dela Rosa scooped up Angelyn, darted to the railing of an outdoor pedestrian bridge and threw the girl over the side. The act was captured by mall surveillance cameras, and shoppers saw Angelyn hit the ground.

Kathlyn Ogdoc testified during the trial that she glanced at her mother just after the fateful moment.

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

Angelyn was rushed to the hospital but died hours later.

Prosecutors said dela Rosa was a “spiteful, angry and jealous” woman who was infuriated that her daughter had gotten pregnant out of wedlock. They said she killed Angelyn to get back at James Ogdoc, who was the focus of her fury. She later admitted in a videotaped interview with police that she had plotted to kill Angelyn while her family enjoyed an outing at the mall.

Deputy Public Defender Dawn M. Butorac argued that dela Rosa was suffering from a major depressive disorder, which sent her into a “downward spiral.” Dela Rosa’s thinking was so clouded by mental illness she didn’t fully comprehend what she was doing, Butorac said. Dela Rosa entered a plea of not guilty by reason of insanity.

After seven days of testimony, the jury deliberated for six hours before returning a guilty verdict. It recommended a sentence of 35 years in prison.

Butorac argued Friday that much of dela Rosa’s sentence should be suspended and that she should receive treatment instead. Butorac said that dela Rosa’s mental condition has deteriorated since her arrest and that it will not improve in prison.

Butorac submitted more than 30 letters from family members and friends on dela Rosa’s behalf. Many sat in the benches behind dela Rosa, including her mother who flew in from the Philippines.

“Sending dela Rosa to prison for 35 years won’t repair this family,” Butorac said.

Morrogh said Friday that he was satisfied with the sentence, even though prosecutors had originally wanted a life term for dela Rosa. He called the crime one of the worst he has seen.

“She was one of the people in the world that should have loved [Angelyn] the most,” Morrogh said of dela Rosa. “The despair that ripples out from a crime like this will last 100 years.”