Case Study: Washington, DC Sniper investigation

• The needle in the haystack:
  • 13 shootings
  • 20+ police agencies investigating
  • thousands of license plates checked

  ... 1 plate shows up 11 times in the first 8 days

  ... 8 more victims before it's all over

• A little bit of inferencing would have gone a long way
• Privacy price too high?

Common Thread: Analysis of functionally-private but actually-public information