Justin's own phone leaked his location (through some google-lattitude, or Yelp like service or perhaps gps directly) while Justin drove (or rode with her in a taxi) to her home.
How would they have gotten my GPS location? And how would they have figured out which one was her house. I was in her neighborhood and stopped multiple places that were 'significant' to her as a kid. Any of them could have been her house. And I wasn't at anyone for more than 60 seconds