The Law: Speak, Voiceprint

It was just after midnight on May 22, 1970, when St. Paul police headquarters got an anonymous call asking help for a woman about to give birth. Two policemen sped to the scene but found only a darkened house. While one policeman went round to a back door, a sniper suddenly opened fire from across the street. The second policeman fell mortally wounded.

It seemed a random attack on "police in general," and the only clue was the telephone call, which had been routinely taped. To find a matching voice, police interrogated 13 women...

Want the full story?

Subscribe Now

Subscribe
Subscribe

Get TIME the way you want it

  • One Week Digital Pass — $4.99
  • Monthly Pay-As-You-Go DIGITAL ACCESS$2.99
  • One Year ALL ACCESSJust $30!   Best Deal!
    Print Magazine + Digital Edition + Subscriber-only Content on TIME.com

Learn more about the benefits of being a TIME subscriber

If you are already a subscriber sign up — registration is free!