ST. PETERSBURG — Police said a weekend shopping trip turned sour after a gun accidentally went off and struck a woman's leg at a Starbucks inside Tyrone Square Mall.Police said Pinellas Park residents Pamela Beck, 51, and her friend Amie Peterson, 38, went to the coffee shop at about 4:30 p.m. Sunday.As Beck reached to pay for her order, she dropped her purse, causing a .25-caliber firearm inside to discharge.Peterson, who was standing behind Beck, was hit once in the left leg, police said. She didn't realize she'd been hit until she looked down and saw blood. No one else was injured.Peterson was treated and released from Bayfront Medical Center. Beck told police her father gave her the gun about a year ago and she's kept it in her purse since then. She said she'd forgotten it was there, and had never taken it out to clean or service it.Beck does not have a concealed weapons permit. Officers referred the case to prosecutors.