Evidence in the Courtroom
When a crime is committed, or when a car accident happens, only the people involved know what really occurred. How then, can a judge or jury discovery the truth at a trial that takes place months or years later?
Judged and juries must rely on the evidence. Let us consider the types of evidence and some of the rules that govern them.
The most common type of evidence is eyewitness evidence the testimony of people who saw or heard what happened. A lot of weight is placed upon this evidence (even though it is probably the least reliable type). This type of evidence is controlled. A witness can only say what he saw or heard directly.
For instance, a witness must be someone who saw the accused assault the victim. A witness cannot testify that someone else told him that the accused assaulted the victim unless he was told by the accused himself. This sort of testimony is hearsay and inadmissible as evidence.
Only an expert witness can testify to something other than what he saw or heard. An expert can provide opinions on technical matters in areas such as medicine, engineering, etc. This is permitted because it is not reasonable to expect a judge or jury to be able to form their own opinions or conclusions on technical matters.
All evidence, other than eyewitness evidence, is called circumstantial. Such evidence is things like objects (the murder weapon, clothing, etc.) or documents. The party introducing circumstantial evidence must establish what it is. For instance, the police officer who found the murder weapon will be called to the stand to identify it. A document must be authenticated. The best way to do this is through the testimony of the writer or someone who signed or witnessed the document.
How do we know if evidence is admissible? Generally, evidence is admissible if it is material and relevant to some issue in the case. There are exceptions to this. As we saw above, hearsay evidence is inadmissible. This is true even if it sometimes seems relevant.