"The person that I know was always there for the kids," Walcott said.
Karanwi and Walcott told jurors that although they don't condone Tata leaving the children alone before the deadly blaze began, they still believe she is a good person.
Tata's sister, Jennifer Tata, testified her sibling was distraught right after the fire.
"She felt really, really bad about what had happened to the kids," she said.
But when questioned by prosecutor Steve Baldassano, Jennifer Tata told jurors her sister was "hard to handle" as a teenager and didn't get along with their parents. She testified their parents, particularly their mother, didn't want Jessica to open the day care without going to college first.
"Is it safe to say she knew full well that leaving kids alone is just dangerous?" Baldassano asked Jennifer Tata, who is a nurse.
"Yes sir," she replied.
Tata fled to Nigeria after the fire but was captured after about a month and returned to the U.S. in March 2011. She has remained jailed since then. Tata was born in the U.S. but has Nigerian citizenship.
Her brother, Ronald Tata, told jurors it was his idea for his sister to go to Nigeria to get advice from their father, who lived there. He said their mother didn't want his sister to go because "it would look bad."
Ronald Tata said his sister should be held accountable for what she did, but he also asked the jury for mercy.
"I believe in justice and not vengeance," he said.
Tata also faces three additional felony murder counts and other charges in relation to the other children killed and injured in the fire.
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