The incident took place around 3:30 p.m. when police say a mother left her sleeping 3-year-old child alone in the car with the window partially rolled down while she shopped at a Dollar Tree Store in Pittsburg.
The mother told police she walked away from her car for about three minutes, but a witness told ABC7 it was much longer than that.
"We were knocking on the window (and) the baby wasn't responding," said witness Carol Payne. "So I ran in the store and got a man here so somebody could get the baby. A security guard happened to be driving by so we stopped him and he was able to pull the window down."
Payne said after the security guard pulled on the window, the toddler inside was still not responding.
"They were running in, trying to get water to put on his little face," Payne said. "We didn't know what direction the mother came from but she was gone for more than 10 minutes. We know that for a fact."
Police interviewed the mother for quite some time. At one point, she was in the back of a police car. While she was not arrested on Friday, police said she could be charged with child endangerment if the district attorney decides to pursue the incident.
The toddler was transported to an area hospital as a precaution.
Police want to remind citizens that children and pets should not be left unattended in a parked vehicle, especially as the weather gets hotter.