The koala is one of the few mammals, other than primates, to have fingerprints.  Their fingerprints are very similar to human fingerprints.  According to an infamously dubious, free, online encyclopedia, human and koala fingerprints are so similar that “even with an electron microscope it can be quite difficult to distinguish between the two.”

Crime Scene Investigator: Here’s the gun from the murder scene.

Forensic Scientist: Thanks.  Once I just take a look at this gun with my trusty electron microscope, I will be able to pinpoint the killer immediately.

Looks in electron microscope.

Forensic Scientist: I see the prints.  It looks like I’ve narrowed it down to two suspects.  But it’s quite difficult to distinguish between the two, even with my electron microscope.

LATER:

Behind one-way glass, a witness looks at the two suspects in a police line-up.  A 46 year-old man with a history of violence and drug addiction …and…  a 25-pound koala with a pouch full of revenge.

The slang phrase “going postal,” as in getting uncontrollably furious and violent, derives from tragic incidents involving United States Postal Service workers. Between 1986 and 1997, more than 40 people were murdered by spree killers in over 20 acts of workplace violence.  You know what hasn’t murdered 40 people?  E-mail.