Arlington police said the suspect rang a doorbell at a back service entrance. A 26-year-old female employee opened the door and was shot, said Detective Crystal Nosal, a police spokeswoman.
Nosal said it was unclear whether the employee and the shooter exchanged words and whether he was after merchandise or money. Police said the unidentified victim suffered a wound to her right shoulder and was in serious, but stable condition at an area hospital. Her injuries are not considered life-threatening, Nosal said.
The store is currently closed while police investigate the incident, and they are expected to release surveillance tape in hopes of identifying the assailant.
Apple has also released a brief statement about the shooting:
"We are shocked by this senseless act of violence and our thoughts are with this co-worker and her family," said Steve Dowling, a spokesman for Apple's corporate headquarters in Cupertino, Calif. "We're working with police to catch the person who committed this act."