Watch this dramatic video of a Florida deputy racing to rescue a toddler from a hot car

On a steamy summer day, June 17, 2018, Officer Bill Dunn from the Seminole County Sheriff’s Office got a call he wouldn’t soon forget.

The caller reported a stolen vehicle, possibly with a child inside, at an apartment complex in Sanford, Florida. When Dunn arrived, he saw the car, a 2005 Toyota Corolla, with the windows rolled up. A girl was inside, her eyes fluttering, going in and out of consciousness.

Newly-released video shows Dunn running with the child limp in his arms.

“Sadly I didn’t think she was alive when I got to her,” Dunn said in the video. “ I didn’t feel a pulse.”

Dunn sprinted to his car, turned on the air conditioning and rushed to a nearby hospital. Dash cam video and audio show Dunn trying to speak life into the unconscious child.

“It’s OK, baby. Talk to me. You’re OK,” he said.

On the sheriff’s office Facebook page, he says once she was in his air-conditioned patrol car, she slowly started showing signs of life.

“Once the cold air hit her, I saw her eyes fluttering,” he said.

“I remember one thing distinctively,” he said. “Putting my hand on her chest and feeling her heart racing. That was a good thing.”

The child, despite being in the car for roughly 12 hours, survived. According to WESH2, her mother, Casey Dyan Keller, 33, was arrested on charges of child neglect with great bodily harm. She was booked into Seminole County jail on $15,000 bond.

Authorities said Keller took her three children to a liquor store the night before. Upon returning home, she accidentally left one child in her vehicle. When the mother saw the child wasn’t at home the next morning, she called 911 reporting her car stolen.

“My baby’s missing,” Keller says in a 911 call obtained by ABC News. “I went to get her in the car, and my car’s missing and my baby’s missing.”

Police said Keller made up the story about the car being stolen.

It’s unclear whether the Florida Department of Children and Families is involved or whether the child is in the mother’s care.

The girl was reunited with Dunn three days later. Video shows the duo hugging each other.