LAWTON, OKLAHOMA: A mother shared some heartbreaking final words before being executed by lethal injection for claiming the lives of her children. Christina Marie Riggs, a nurse, was put to death in Arkansas in May 2000 after spending just three years on death row. She was convicted of murdering her children three years before and had planned to take her own life, but was unsuccessful.

"There is no way words can express how sorry I am for taking the lives of my babies," she said according to The Mirror, adding "Now I can be with my babies, as I always intended."

Christina Riggs became the 18th woman in the US to be executed

As a result of her horrific crime, Riggs became the 18th woman in the US to be executed and was the youngest woman to be put to death at just 28. In Arkansas, it was the first time a woman had been executed in the state since 1845.

She killed her two children Justin, five, and Shelby Alexis, two, by injecting them with potassium chloride and strangling them. Riggs later penned a suicide note and took a massive overdose of antidepressants.

Why did Christina Riggs kill her children?

The mother initially claimed that she was overwhelmed by the trauma she endured as a nurse after the Oklahoma bombing in 1995 and it sent her into a deep state of depression. Her mother said Riggs worked at the bomb site, but the Veterans Affairs hospital denied this claim, saying she was paid overtime for working at another hospital that day.

Riggs' lawyers said she was innocent due to her being insane when she carried out the murders. Prosecutors disagreed and said the murders were premeditated. "Sometimes I can't think about them," Riggs told the Arkansas Times in 1999, adding "It's like they're being ripped away from me all over again."

Christina Riggs suffered sexual abuse in her childhood

While Riggs was behind bars, it was revealed that she suffered sexual abuse at the hands of her own brother when she was between seven and 13. She was also abused by a neighbor when she was a teenager, she said. "I felt that no boy liked me because of my weight, so I became sexually promiscuous because I thought that was the only way I could have a boyfriend," she claimed.

Christina Riggs first conceived at 16

Riggs first fell pregnant at the age of 16, but gave the baby up for adoption in 1988. Eventually, she struck up a relationship with Timothy Thompson, then at the nearby Tinker Air Force Base. She became pregnant with Justin in late 1991, but Thompson decided not to stay with her.

During the pregnancy, she formed a relationship with sailor Jon Riggs before Justin was born. "As I held Justin in my arms and looked into his little face, I became so scared. Would I be a good mom? Could I give him all he needed?" Riggs wrote in her journal.

Jon and Christina Riggs eventually got married, but their wedding night was marred by tragedy when Christina suffered a miscarriage. To make things worse, the marriage turned out to be bitter as court documents revealed that Jon Riggs had punched Justin so hard in the stomach that he needed medical attention, leading to Christina Riggs falling into depression.

In 1994, they welcomed a baby girl named Shelby Alexis. Christina wrote, "We were so happy. She was so beautiful. I didn't think things could get any better. (Jon) cried. I cried. He was full of so much love for her. The way he looked at her."

However, the marriage later fell apart and promoted Riggs to commit terrible crimes due to financial limitations. She later expressed regret for her actions. "I still believe in the death penalty even though I'm sitting here on death row," she once stated, adding "In my case, I'm glad I have the option."