e-Evidence Insights: Mars Needs Moms; But Science Needs Humans

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"It's an inexact science."  We've heard that phrase often.  But, how often have we heard it in reference to DNA?  Usually, we hear it more in terms of how it identifies a particular suspect with astronomically-high odds, such as, 'one-in-a-million'.  In other words, it must be him because mathematically, it couldn't possibly be anyone else.

Consider the very bad luck of our suspect in today's story:

 

  • A murder was committed.
  • The suspect's DNA was found on tape used to gag the victim.
  • Based on this evidence, he was promptly arrested.

Now, factor in the very good luck of our suspect in today's story:

  • He had an alibi.
  • He was able to prove it beyond all doubt (i.e, it wasn't his mother claiming that he'd been with her the entire time – he was in a hospital).

In fact, he was nowhere near the scene at the time of the murder; nor was he ever at the scene.  Yet, he spent five months in jail before he was eventually exonerated.

This appears to be a bizarre case of transference.

Furthermore, DNA is not necessarily like snowflakes; sometimes, two samples are identical (at least within the range that law-enforcement would feel comfortable arresting and prosecuting a suspect).

The moral of this story?  We rely on science; but sometimes, science must also rely on us.