Talley is charged with involuntary manslaughter and possession of a firearm during the commission of a crime in connection with the July 26, 2009, death of Lane Alan Gann Jr., 19.
The jury, which is expected to continue deliberations today, is poised to determine whether Talley was reckless to the point of criminal negligence the night of Gann's death; the two had not met prior to a party at a mutual friend's Glade Road, Acworth, home.
Her attorney, Marc Clark, asked jurors to find that the shot through Gann's heart was an accident because Talley was not intoxicated and meant to fire the gun in a different direction.
Previous testimony indicated Talley and Gann were discussing the firearm, and Gann may have thought it was a BB gun and issued a challenge for Talley to fire it.
Jurors heard Talley's interview with police, in which she said she had been drinking and had no training or experience with the .22 rifle, but meant to fire it away from Gann.
District Attorney Joe Campbell told jurors in closing that Talley's firing of the Magnum round in a neighborhood and her pointing it in a person's direction after retrieving it from the trunk of her car was reckless and grossly negligent. He asked jurors to find her guilty of the charges.
The jury has three options -- find Talley guilty of the felony charge she faces, find her guilty of misdemeanor involuntary manslaughter or not criminally negligent, or acquit her, Clark said.
Talley told police she was carrying the firearm to protect her sister from threats. But the man who allegedly made those threats was not present at the party that night, Campbell said.
The two attorneys, who exchanged heated words with one another during Thursday's proceedings, also disagree on why Talley fled the scene after the shooting. She was found about an hour later and had apparently crawled under a mobile home miles away to hide.
Clark and Lt. Robert Moultrie, the lead investigator on the case whose testimony wrapped up Thursday, told jurors they believe Talley ran because she was panicked and frightened.
But Campbell told jurors Talley ran because she knew she did something wrong and was scared of the consequences.
In her interview with police, Talley, crying and distraught, said she had never fired her boyfriend's gun before but knew where the safety was located. She added that she had loaded the magazine earlier that day, but did not realize she had also cocked the gun.