Fulton Superior Court Judge Henry Newkirk told the jury that there must be knowledge of the string in order to convict Thompson.
After the verdict was announced, Newkirk read a statement from the jury.
"We the jury are disappointed and frustrated with the charges brought by the state," the jury wrote. "While we found the defendant negligent in leaving young children unattended, we cannot find her guilty of criminal negligence as required by the charges."
The verdict angered Max’s father and grandfather, who spoke through tears late Friday afternoon.
“How you let someone do that to a child and not say someone is guilty, I just don’t understand,” said Wayne Stephens, the grandfather.
Max’s father, who has not spoken publicly about his son’s death until this week’s trial, said he was frustrated and saddened by the verdict.
“I don’t feel like we had a fair trial,” Jeff Stephens said. “He (Newkirk) narrowed the charge so finely, he ruled from the bench. I believe that a lack of supervision is the cause of death in a child that age.”
Heidi Stephens testified Wednesday that when she left her 3-year-old son with the babysitter, he was happy and watching a cartoon, something he didn't do at home. Max hardly noticed as his mother went out the door to go to work.
The next time Stephens saw her son, later that morning, he was unconscious and near death at North Fulton Hospital. Thompson had found him unresponsive on the sliding board in back of her house, a piece of twine around his neck.
At Children’s Healthcare of Atlanta at Scottish Rite, Max underwent additional tests that were reviewed by three doctors, Stephens said. All three told Max’s parents that he would not recover. He died the following day, July 9, 2014, after being removed from life support.
Prosecutors said Thompson left Max and two other children alone outside for 18 minutes while she went inside her home to discipline another child and use the bathroom. While inside, Thompson used her phone to find college football schedules, her cellphone records showed.
Thompson’s attorneys said it was only a matter of minutes that she was inside her home, and that she could still see and hear the children through windows and an open door. In interviews with Alpharetta police, Thompson admitted she could have been more observant the morning Max was injured, July 8, 2014.
But her actions were not criminal, Garland said outside the courthouse.
“Not every tragedy should end in incarceration,” he said. “Janna was charged with murder, and Janna did not commit murder.”