There really isn't enough evidence to prove that he committed the crime, so it's (highly) 'improbable' that he'll be convicted.
The story includes a number of absurd 'improbabilities'. [=improbable events or situations]
The team made an 'improbable' comeback.
(..) Damn it man, I am a doctor, not physicist. Are you actually suggesting they're from the future? If you eliminate the impossible, what ever remains, however improbable... must be the truth. How poetic. Then what would an angry future Romulan want with captain Pike? As captain he does know details (..)2009 Star Trek