The evidence that law enforcement officers collect is one of the most important parts of a criminal case. Without evidence, ranging from physical evidence like DNA or fingerprints to testimony from witnesses, or even a confession from the person accused, it is typically not possible for a prosecutor to build a case.
After all, the law requires that the prosecutor convince either the judge or the jury presiding over the case beyond a reasonable doubt of the guilt of the accused person. Given how important evidence is to a criminal case, law enforcement officers often have a reason to collect as much evidence as possible, and sometimes they make mistakes in doing so.
Challenging that evidence is a common part of an initial criminal strategy. However, reviewing the evidence used in the case could also play a role in your appeal of a previous criminal conviction.
As a general rule, you can’t just appeal because you’re unhappy with the ruling. You need to have grounds for an appeal. A violation of your rights could give you grounds to appeal a conviction. People can escalate their appeals if they don’t win initially, possibly up to the Supreme Court in rare cases.
There are things police officers can do as part of their investigation and other things that violate the civil rights of the people they investigate. For example, officers may try to get people to invite them inside or otherwise waive their civil rights in order to conduct a search.
However, some officers who will do inappropriate or underhanded things, such as claiming they thought the crime was in progress without any valid reason to say so. Other times, they might force their way into a property without permission or even violate the rules and limitations laid out in a search warrant. If you can demonstrate that the search violated your rights, that could be grounds for an appeal.
Given how important genetic evidence has become to modern court proceedings, law enforcement officers must be more careful than ever before in the process of collecting, storing and analyzing evidence.
In some cases, the police may not follow the correct protocol for the chain of custody for an individual piece of evidence. Inadequate records or indications of contamination could be a reason to challenge evidence that was used in part to secure your conviction. Reviewing the chain of custody for the evidence and also the circumstances under which police collected it could help you determine if you may have grounds for an appeal due to the inadmissibility of the evidence used.