Harpster tells police and prosecutors around the country that they can do the same. Such linguistic detection is possible, he claims, if you know how to analyze callers’ speech patterns — their tone of voice, their pauses, their word choice, even their grammar. Stripped of its context, a misplaced word as innocuous as “hi” or “please” or “somebody” can reveal a murderer on the phone.
So far, researchers who have tried to corroborate Harpster’s claims have failed. The experts most familiar with his work warn that it shouldn’t be used to lock people up.
Prosecutors know it’s junk science too. But that hasn’t stopped some from promoting his methods and even deploying 911 call analysis in court to win convictions.