Dorothy Whipple remembers the first time she met Tasha Trotter.
Trotter was visiting her daughter, now 3. The child had been living with Whipple's family in Naples after the mother lost custody.
Mother and child were riding together in the back of a car, Whipple recalled.
The child would not stop screaming until the two of them were separated.
The incident recalls the troubled history of a woman who on Friday, authorities say, walked into her mother's St. Petersburg home and fatally stabbed her 4-year-old son, Joseph Artis IV.
Relatives on both sides are struggling to understand what drove Trotter, who has a history of mental illness, to commit such an astoundingly brutal crime.
"Nobody could have stopped her?" Whipple asked Monday. "They didn't protect their baby, and look where he's at now."
The boy had been living with his grandmother, Carolyn Trotter, since his mother lost custody in 2011.
That arrangement came after two years of upheaval documented by the Department of Children and Families and Pinellas County courts, including a domestic violence injunction filed against the boy's father, Joseph Artis III, when the son was 9 months old. That injunction was later dismissed.
Joseph Artis III's record with the Florida Department of Law Enforcement includes arrests for robbery, aggravated battery and grand theft.
Trotter's family said the woman suffers from various mental illnesses, including schizophrenia and bipolar disorder. Whipple said Trotter and Artis III met in a Boley Centers facility for people with mental disabilities.
They had two children. The youngest, Kristian, 3, was in foster care for a time and now lives with Whipple's sister Gwendolyn Rose in Naples.
Whipple now wishes she had somehow assumed custody of the young boy.
"We just hate that we didn't make that decision to go ahead and keep him, but we thought we were doing the right thing by leaving him with the grandmother," Whipple said.
Whipple remembers that Joseph loved his mother. When Whipple spoke to him over the phone, he was happy, she said.
Claire Wiseman can be reached at email@example.com or (727) 893-8804. Follow @clairelwiseman on Twitter.