In all criminal cases there are 2 categories of evidence: direct evidence and circumstantial evidence.
Direct evidence is anything the witness observed through his senses. “I saw this” or “I heard this” or “I could smell alcohol on his breath” are common examples of direct evidence. Many consider this type of evidence to be more reliable because there is less room for interpretation and the testimony can they be judged based upon the jurors’ view on the witness’s credibility.
Circumstantial evidence is evidence of observation that, if accepted, allows you to assume another fact. The most common example used involves rain. Imagine you are inside of a windowless building and you see some people enter and they are wet, one even is collapsing a wet umbrella. What do you conclude? Perhaps, it is raining. And, that would be a logical explanation of events.
Most cases have a combination of direct and circumstantial evidence. However, the law allows for a conviction to be sustained on circumstantial evidence alone, provided that every reasonable hypothesis is ruled out. What does that mean? Well, let’s return to our rain analogy. What if the defense presented evidence that the weather reported a sunny day? And, what if he established the building just installed a new sprinkle system. Is it possible the sprinkler system went of and wet everyone? Maybe, maybe not. But, to defeat a circumstantial case, you try to present other plausible, or reasonable, explanations for the observed facts to come to different conclusions. Remember, the defense isn’t required to prove up a better or more believable version of events- rather, they just need to present a credible version.