West Valley City police have arrested a 14-year-old who allegedly stole a woman's purse at Walmart Friday afternoon.

A 29-year-old woman left the store at 5600 West 3180 South with her diaper bag in her shopping cart, said West Valley City police Lt. Bill Merritt. When she turned to put something in her minivan, the teen allegedly jumped out of a Ford Taurus and grabbed the bag, which had her wallet inside.

The Taurus drove away and officers pulled it over near 3675 West and 2150 South. Inside, they found only a female driver. Officers took her into custody, and she admitted the purse snatcher was her brother, Merritt said.

Meanwhile, officers contained the area where the car was pulled over and waited. After a time, the teen tried to "nonchalantly" walk across the street, apparently thinking officers had left, Merritt said.

He initially denied stealing the bag, but stopped after his sister identified him, Merritt said. He was arrested on suspicion of strong-arm robbery. The bag was inside the car, and wallet was found intact across the street. The woman had no cash inside, and lost only a coin purse containing pennies.