The following may or may not apply here, but forensic investigators must always be aware of and quard against the phenomenon of "matrixing" aka pareidoia:
See Wiki page:
http://en.wikipedia.org/wiki/Matrixing
Pareidolia (Redirected from Matrixing)
"Pareidolia (/pærɨˈdoʊliə/ parr-i-DOH-lee-ə) is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant, a form of apophenia. Common examples include seeing images of animals or faces in clouds, the man in the moon or the Moon rabbit, and hearing hidden messages on records when played in reverse."