During a hug between a woman, 24, and her boyfriend, 18, she complained the gun tucked in his waistband was causing her discomfort.
But police say that when he removed the gun, it discharged and a bullet hit the woman, who died of her injuries after being rushed to a hospital.
Phoenix police Sgt. Tommy Thompson said the shooting appeared to be accidental but the investigation would be submitted to the Maricopa County Attorney's Office for review, KPHO-TV reports.
Police did not release any names in connection with the incident.
Here's a report from KTVK-TV: