“including how frequently they described their crimes using the past tense.”
As opposed to describing their past crimes in the future tense? What?
Maybe the speaker's a soulless psycho, too.
Or hey, maybe the findings are a pile of Obama!
A lot of colloquial past description is done in the present tense. Non psycho murderer: “so I go into this liquor store, you know? And this guy behind the counter sees me coming and I can tell he knows I’m gonna do something...”