Evidence is the cornerstone of any criminal trial. Without it, you just have accusations, and if the state accuses you of a crime, they have to be able to prove – using evidence – that it is beyond any reasonable doubt that you did that crime. This means that evidence is vitally important in a trial, which is why your criminal defense lawyer in Oklahoma City will both look for evidence that can exonerate you (or at least cast doubt on the prosecution’s case) and also do everything possible to call into question the evidence the prosecution is trying to bring.
From an Oklahoma City Criminal Defense Lawyer: Evidence in Criminal Trials
Types of Evidence
Evidence can be broadly categorized into physical, documentary, testimonial, and digital evidence. Physical evidence is, of course, tangible items that can be seen and handled, such as weapons, clothing, and fingerprints. Documentary evidence includes anything written or printed, like letters, contracts, or official records. Testimonial evidence comes from witnesses who provide oral accounts of what they observed. Digital evidence includes anything available as electronic data, such as emails, digital video, etc.
Each type of evidence has unique characteristics and requires different methods of collection, preservation, and presentation. Physical evidence must be handled very carefully, properly documented, and then carefully preserved to avoid any contamination or degradation. Chain of custody for physical evidence is very important: the prosecution must be able to show that any physical evidence they bring has been tracked from the moment it was collected until it is presented in court.
Documentary evidence, meanwhile, must be authenticated to confirm its origin and accuracy. Testimonial evidence depends on both the willingness of a witness to give a testimony as well as their overall credibility and reliability. Witnesses are usually subjected to cross-examination to assess their truthfulness. Digital evidence, given its intangible nature, requires specialized tools to retrieve, analyze, verify, and present.
The Collection and Preservation of Evidence
Law enforcement officers, forensic experts, and legal professionals all need to follow certain protocols to ensure that any evidence collected was done so legally and remains uncontaminated. The Fourth Amendment to the U.S. Constitution protects citizens against unreasonable searches and seizures, which means that law enforcement must obtain warrants before they can search or seize private property without the owner’s permission, and this warrant should be given only if the police are able to provide convincing probable cause.
Once evidence is collected, it must be preserved in a way that maintains its integrity. For physical evidence, this often means using sealed bags, evidence lockers, and controlled environments that prevent both environmental contamination or tampering. Digital evidence requires secure storage on encrypted devices and special protocols that prevent data corruption or loss. Proper documentation at every stage of handling is vital: the prosecution must be able to show a clear chain of custody that can be presented in court to verify the evidence’s authenticity.
Testimony of Expert Witnesses
Expert witnesses have special knowledge in fields like forensic science, medicine, psychology, and digital forensics. Their testimony is used to help explain complex evidence to judges and juries which would otherwise be meaningless, or where lay persons wouldn’t be able to understand the deeper implications of the evidence. Experts put the evidence into context and can have a big influence on a trial’s outcome.
In Oklahoma, expert witnesses have to have certain qualifications. The Daubert standard is federal law for vetting expert witnesses, and it comes from a landmark U.S. Supreme Court case. Oklahoma has chosen to adopt this standard to determine whether an expert’s testimony is based on scientifically valid reasoning and methodology.
The goal is to make sure only credible, relevant, and scientifically sound evidence is presented in court, and this is just one of many reasons it’s essential to work with an experienced criminal defense lawyer. An attorney with Oklahoma City experience will know the state laws and have experience with the local judges, of course, but they will also have a network of experts to draw on for your case.
The Admissibility of Evidence
Any evidence either side in a criminal case wants to bring must meet specific criteria to be considered admissible. In general, the evidence must be relevant, material to the charge, and competent. Relevance refers to the evidence’s ability to prove or disprove a fact that is important to the case. Materiality pertains to the significance of the evidence in establishing an element of the crime. Competence speaks to the evidence’s reliability and its compliance with legal standards.
Rules of evidence, such as the Oklahoma Evidence Code, provide guidelines for determining whether a piece of evidence is admissible, and judges have the discretion to exclude evidence that they believe is prejudicial, confusing, or misleading. Additionally, certain types of evidence, such as hearsay, are generally inadmissible unless they fall under very narrow established exceptions. One of the tasks of your lawyer will be to bring admissible evidence on your behalf and to challenge the admissibility of the evidence against you wherever possible.
Evidence and Constitutional Rights
As mentioned earlier, the Fourth Amendment protects you from unlawful searches and seizures. Any evidence law enforcement obtains in violation of this amendment can be ruled inadmissible, so your lawyer will carefully check that your Fourth Amendment rights weren’t violated in obtaining evidence against you.
The Fifth Amendment provides protections against self-incrimination: you cannot be forced to be a witness against yourself. Meanwhile, the Sixth Amendment guarantees you the right to a fair trial, which includes the right to confront witnesses against you. This means your lawyer can cross-examine all witnesses who testify against you, which gives them a chance to disprove the reliability and credibility of the evidence those witnesses give in their testimony.
Forensic Evidence
Forensic evidence refers to a pretty wide range of scientific techniques, like DNA analysis, fingerprinting, ballistics, and toxicology, that can sometimes offer objective data to corroborate or contradict other evidence.
DNA evidence can, when done correctly, uniquely identify individuals, and it has been used to convict the guilty, exonerate the wrongfully accused, and identify previously unknown perpetrators. Fingerprint analysis remains a staple of forensic science, of course, and ballistics analysis examines firearms, bullets, and gunshot residue to provide insights into the mechanics of a crime, establish timelines, and identify weapons. Toxicology is the study of drugs and poisons, and toxicologists can analyze bodily fluids and tissues to detect the presence of substances that may have contributed to a crime.
Forensic evidence is not foolproof, though, and usually this evidence doesn’t prove anything on its own. Instead, it simply provides data, which must be interpreted and applied (or questioned) by skilled lawyers. For example, finding four different fingerprints at a burglary scene can help investigators by providing a starting point for whom to look at, but those fingerprints can’t say which of the four committed the crime, or even if one of them did. The actual burglar may have left no fingerprints at all. Forensic evidence against you has to be used carefully and it can be called into question by a good lawyer.
Evidence is important in a criminal case, but even more important is the lawyer who knows how to use it. Contact our team today at Cannon & Associates to talk to a fierce advocate for your criminal defense.