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.
(..) They're all around you. Smash the piñatas!!! Yeah! You guys are on fire! Hmmm, it's so delicious. We did it! My improbable plan worked! ("Hello!") Seven minutes up yet? What the nuts happened here?!? Oh, we killed all the zombies that Princess Bubblegum and I raised from the dead. (..)2010 TvShow: Adventure Time Title: Slumber Party Panic Season: 1 Episode 1