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?

Single instance of a common pattern: Analysis of functionally-private but actually-public information