The case is now in the hands of the Orange County District Attorney's Office, though Fullerton police say they still wish to speak to additional witnesses.
The child's mother, 35-year-old Jacqueline Marie Hernandez, was taken into custody on suspicion of felony child abuse, according to Fullerton police.
The video shows a black Mercedes turning onto W. Malvern Avenue from N. Euclid Street. As the driver makes the turn, the front passenger door opens, and the toddler tumbles out of the vehicle and into the roadway.
Mother arrested after toddler falls out of moving SUV in Fullerton
Thankfully, the driver of a white car behind the SUV stops on a dime, preventing further injury.
Investigators say the driver of the SUV was the child's mother. The video shows her getting out, rushing around the vehicle, and picking up the child before quickly driving away.
A dash camera video was posted to social media, and a woman who works at the intersection saw the video on her timeline.
"I have twins that same age, and they're always in their car seat, rear-facing, so I couldn't really comprehend why it was OK to put the baby in the front seat with no restraints, and then on top of that, the risk of the baby opening the door," said Natalie Quintanilla, who reported the video to police.
Quintanilla quickly realized the intersection at the center of the case was right outside of her office.
"As soon as I saw it said Malvern and Euclid, my first thoughts were to let police know and everything because it's a busy street," Quintanilla said.
She called Fullerton police. Surprisingly, she learned nobody had reported the incident to police when it happened on Jan. 20.
But after calls like hers and the video gaining traction online, police say a witness came forward, leading them to Hernandez in La Habra.
They say the child sustained injuries consistent with the fall and was taken to the hospital for treatment. The toddler is expected to make a full recovery.
"I was shocked that she even got arrested because we all make mistakes," a neighbor told Eyewitness News.
The man who owns the house next door asked not to be identified, but said police were seen at Hernandez's home in recent days.
"I always see them getting loaded up into the cars in seatbelts, in car seats," the neighbor said.
Eyewitness News tried knocking on Hernandez's door after she was released from custody on bond, but despite the sound of children inside, no one answered the door.
"I hope everybody can forgive her. She's a good person," the neighbor said.
The incident remains under investigation. Anyone with information is encouraged to contact the Fullerton Police Department's Sensitive Crimes Unit, Detective H. Rios, at (714) 738-6782 or hrios@fullertonpd.org.