Police think the teen, a recent high school graduate and new driver, missed a stop sign, lost control of the car and careened down an embankment into the pond.
Once the deputy spotted the submerged car, authorities had to bring in a dive team to confirm it was Mosier's car because the water was so murky. They then found the teenager inside, according to the Banner-Herald.
The search for the girl included several Athens-area law enforcement agencies. After several days coming up short, Baird told the newspaper officers were retracing their steps.
“We went over everything that had been done and mapped out every area we had looked,” he said.
And they finally found her.
"It's a rough time for the family, but they do have some resolution," Baird said.
The Georgia State Patrol is still investigating the crash.
Chelsea Prince contributed to this story.