Driven by “anger, hatred and revenge,” a Fairfax County woman plotted to kill her 2-year-old granddaughter by tossing her off a 44-foot walkway at Tysons Corner Center last November, Fairfax County’s top prosecutor said in court Monday.

Carmela Dela Rosa, 50, hatched the plan during a family outing as a way to get back at little Angelyn Ogdoc’s father, James Ogdoc, prosecutors said. They said she blamed him for getting her daughter, Kathlyn Ogdoc, pregnant out of wedlock and splitting her from the family.

“This defendant killed this child because she was a spiteful woman,” Fairfax County Commonwealth’s Attorney Ray Morrogh said at the opening of Dela Rosa’s murder trial. “It was her way or the highway in life.”

But Public Defender Dawn Butorac sketched a very different portrait of Dela Rosa, who entered a plea of not guilty by reason of insanity. Butorac said Dela Rosa was a loving grandmother who suffered from “major depressive disorder” and had tried to commit suicide several times. In the months before the Nov. 29 death of Angelyn, Dela Rosa’s mental health issues were exacerbated by the family’s financial problems and the death of her brother in the Philippines. She couldn’t cope with the strain, Butorac said.

“August until November 2010 was a downward spiral” for Dela Rosa, Butorac said during her opening statement. “Her thought process turned psychotic.”

The trial, which is expected to last as long as 10 days, will revolve around Dela Rosa’s mental state. If Dela Rosa is found guilty of murder, she could face a sentence of up to life in prison.

During that trip to the mall, Morrogh told jurors, Dela Rosa fought with her husband, Leandro, and son, David. But Morrogh said what really set Dela Rosa off was a call from James Ogdoc to Kathlyn Ogdoc.

Dela Rosa “was angry and jealous this man was intruding on private time with the family,” Morrogh said. “She felt this man stole her child from her too soon.”

At that point, Morrogh said, Dela Rosa began planning to kill Angelyn. Morrogh said Dela Rosa, who is deeply religious, never got over the fact that Kathlyn Ogdoc got pregnant out of wedlock.

James Ogdoc and Kathlyn started dating at Bishop O’Connell High School in Arlington in 2004, Morrogh said. The pair, both children of Filipino immigrants, built a “strong relationship” and continued seeing each other through college, he said. They were married shortly before Angelyn was born in 2007.

In an April 2009 letter to her daughter that is in the court file, Dela Rosa said she was hurt by Kathlyn Ogdoc’s choices. “I feel very betrayed and disappointed,” she wrote. “I wanted you to enjoy your 20s without any responsibility of a husband and child.”

Butorac said Dela Rosa was first diagnosed with major depression disorder in June 2000, shortly after her father died in the Philippines. Treatment kept her mental health issues in check at first, but in 2008 Dela Rosa took a turn for the worse, Butorac said.

In 2010, Dela Rosa tried to commit suicide by swallowing pills and then drove her car down a steep embankment in the Shenandoah Mountains, Butorac said.

In the week before Angelyn’s death, Dela Rosa stayed home while her family took a beach trip. “During those five days, she didn’t shower, didn’t eat, didn’t see anyone,” Butorac said.

When the family returned, Dela Rosa seemed in better spirits, so the family planned the outing to the mall, Butorac said.

Monique Cox, who was visiting Tysons Corner that evening, testified that she and her fiance were on the sidewalk when they heard voices from a walkway above. She said she glanced up and saw what she thought was a child’s jacket falling.

“When it hit a tree, we saw a face,” Cox said. “That’s when we started screaming.”

Cox said Angelyn landed on the pavement a few feet from her and her fiance. They knelt and stayed with her as a crowd gathered and, later, an ambulance arrived.

“If we had known it was child, we could have caught her,” Cox said.

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