"Wednesday was the worst day of my life," 4-year-old Abby tells CNN affiliate KCPQ. She recently helped the Whatcom County, Washington, Sheriff's Office crack a robbery case when she reported seeing her babysitter stealing in her house. Investigators say the 17-year-old babysitter told police that two armed black men broke into the child's Ferndale home. But after Abby told the cops that wasn't true, the babysitter later confessed to being the thief. Watch this video to find out more.