Evidence in a general sense is anything used to try and prove an allegation. In a criminal case, evidence provides reasonably reliable information that gives a more complete picture of a crime. Criminal evidence is often presented in two forms: circumstantial evidence and direct evidence.
In a criminal trial, a blend of both forms of evidence may be presented to the court by the prosecuting attorney and the defense in order to prove guilt or innocence of the alleged criminal.
Circumstantial evidence is presented to help draw inferences in a criminal case about how events tie together. It's also labeled as indirect evidence. Both sides in a trial will search out this type of evidence in order to support the claim they are presenting. Convictions can be obtained by using circumstantial evidence; however, this type of evidence needs to be corroborated in order for a conviction to happen.
For example, circumstantial evidence can come from a witness who viewed a person with a bloody knife standing over someone who was stabbed. Not having seen the act committed, the witness' testimony becomes circumstantial evidence. The witness can describe what they saw. Other facts would be needed to corroborate the witness account and alleged criminal act in order for the accused to be found guilty.
Circumstantial evidence is suggestive evidence that helps build the main point. Whether or not circumstantial evidence is believed will have a large influence on the verdict, especially in cases with little direct evidence. The presentation of circumstantial evidence in jury cases, where the prosecution typically has to prove its case beyond a reasonable doubt, is critical.
Direct evidence is a more straightforward support of the argument being made. This type of evidence does not ask the jury to develop opinions based on circumstance. Its purpose is to provide evidence that shows proof beyond a reasonable doubt.
For example, entering a gun with fingerprints on it as evidence is considered direct evidence. This places a weapon into someone's hand as fact. Video, audio, DNA and even certain types of witness testimony can all be used as direct evidence.
Witness testimony can carry varying weight depending on the background of a witness. The opinion of a forensics expert will likely be taken with a stronger understanding than the testimony of a convict.
Problems in evidence
Evidence itself is a much disputed notion. Some lawyers will argue that there is no such thing as direct evidence, that it is all simply circumstantial. There are questions about to what extent it is even possible to fulfill burden of proof. In the field of law, levels of certainty and evidence are often debated.