Officers responded to an assault with a deadly weapon call on the 3100 block of Strawberry Tree Lane around 11:24 a.m.
According to police, when the victim knocked on John Dodrill's home, he opened the door and pointed a gun at her. The girl's father witnessed the incident and alerted police.
Officers arrested the 53-year-old suspect and confiscated the weapon.
Girl Scouts of San Gorgonio released a statement Monday saying that this was an isolated incident.
"The safety of the girls is of paramount importance to Girl Scouts of San Gorgonio," the statement said. "There is no record of anything like this ever occurring in the past 90 years since Girl Scouts were established in the area. The San Gorgonio Council has established rules for door-to-door and cookie booth selling, and provides mandatory training for all adults and girls."
The organization says girls are trained to never sell cookies without an adult present, unless they are senior or ambassador scouts.
The investigation is ongoing. Anyone with information regarding this investigation was urged to contact Officer Garcia at the Southwest Sheriff's Station at (951) 696-3000.