Making accusations of criminal wrongdoing is easy. Proving those allegations is another matter altogether. This is true specifically because the burden of proof is high, and it is placed on the state. Before penalties can be imposed on an individual, prosecutors must prove beyond a reasonable doubt that he or she committed the alleged crime. To obtain these convictions, prosecutors rely on the admission of evidence. Sometimes this evidence is presented in the form of witness testimony, but other times it is presented in a physical form.
In order for evidence to be admitted at trial, though, prosecutors must show that it is what it claims to be and that it has not been compromised. This issue is often seen in chain of custody matters. In a drunk driving case, for example, the state must prove that a blood sample used for alcohol testing was properly drawn, handled prior to testing and tested without any suspicion of mishandling or contamination.
Also, evidence that is illegally obtained may be disallowed from being admitted into evidence. This is known as the exclusionary rule. For example, drugs that are seized during an illegal traffic stop cannot be used against a criminal defendant in a trial for drug possession or other drug-related crimes. This gives defendants the opportunity to raise questionable police tactics, protect their legal rights and, perhaps, suppress evidence that could be key to a prosecution's case.
Suppressing evidence, when possible, is a critical piece of a criminal defense. However, illegally seized evidence will only be suppressed at trial if it is properly objected to by a party to the case. This takes legal know-how and skill, especially since prosecutors will push back by making arguments to support their position. This is why many Ohioans who are facing criminal charges stemming from search and seizure find it beneficial to obtain the assistance of a skilled criminal defense attorney.
Source: FindLaw, "How to Suppress Evidence," accessed on March 10, 2017