WHITE PLAINS, N.Y. (CBSNewYork) — A mother accused of fatally poisoning her 5-year-old son will not testify in her own defense at her trial.

Prosecutors say Lacey Spears fed her son, Garnett, large amounts of salt through a gastrointestinal feeding tube, causing brain swelling, seizures and death. They believe she administered the salt in his room at Nyack Hospital after he was admitted for seizures. He later died after being transferred to Westchester County Medical Center.

The boy had a special feeding tube in his abdomen that was left over from an illness he had in infancy, which provided Spears with the ability to sicken her son at their home in Chestnut Ridge and then fatally poison him during subsequent hospital stays.

Prosecutors have said Spears purposely sickened the boy to gain attention and called her “a calculated child killer.”

Garnett’s death ended a short life filled with doctor and hospital visits that his mother tirelessly documented in thousands of postings on Facebook, Twitter, MySpace and a blog.

She has pleaded not guilty.