How to Challenge Evidence in a Drug Crime Case
Jan. 26, 2025
Facing charges in a drug crime case can be one of the most overwhelming experiences in life. However, being charged doesn’t mean being convicted. Missouri law provides defendants with rights and legal defenses that can be used to challenge evidence presented by the prosecution.
Reach out to me today at Walker Law in Chesterfield, Missouri, so I can help you understand these rights and the options available to you. This article explores key strategies for contesting evidence in Missouri drug crime cases and highlights how the legal process can be used to your advantage, starting with an experienced criminal defense lawyer.
The Importance of Challenging Evidence
In Missouri, drug crimes can carry significant penalties, including hefty fines, imprisonment, and a permanent criminal record. Convictions often hinge on the strength of the evidence presented by the prosecution.
By challenging that evidence, defendants may weaken the case against them, potentially leading to a reduced sentence, dismissal of charges, or acquittal.
Missouri courts follow specific rules regarding evidence, which must be gathered, handled, and presented properly. Any deviation from these rules can make the evidence inadmissible, giving the defendant a stronger position in court.
Unlawful Search and Seizure
One of the most common ways to challenge evidence in a drug crime case is by addressing how the evidence was obtained. Under the Fourth Amendment to the U.S. Constitution and Article I, Section 15 of the Missouri Constitution, individuals are protected against unreasonable searches and seizures.
Evidence gathered through unlawful means may be suppressed, meaning it can’t be used against the defendant in court. Common issues related to unlawful search and seizure include:
Lack of a warrant: Law enforcement must often obtain a warrant before searching a person, vehicle, or property. If the search was conducted without a valid warrant or without meeting an exception to the warrant requirement, the evidence may be inadmissible.
Exceeding the scope of a warrant: Even with a valid warrant, officers must stay within its limitations. Evidence found outside the specified areas or unrelated to the scope of the warrant can be challenged.
Illegal traffic stops: If drugs were discovered during a traffic stop, the legality of the stop itself can be questioned. Officers must have reasonable suspicion or probable cause to pull a vehicle over.
A criminal defense lawyer can file a motion to suppress evidence obtained unlawfully, asking the court to exclude it from the case.
Chain of Custody Issues
In drug crime cases, the prosecution must demonstrate that the evidence presented in court is the same as what was collected during the investigation. This involves establishing a clear chain of custody—a documented trail showing who handled the evidence, when, and under what circumstances.
Breaks or inconsistencies in the chain of custody can cast doubt on the integrity of the evidence. For example:
Was the evidence properly stored to prevent tampering or contamination?
Were all transfers of evidence accurately recorded and documented?
Is there any indication that the evidence was mishandled or altered?
By questioning the chain of custody, a criminal defense lawyer can undermine the prosecution's case and potentially have critical evidence excluded.
Questioning the Reliability of Testing Methods
In many drug crime cases, laboratory testing is used to identify the substance in question and confirm it’s an illegal drug. However, the reliability of these tests can often be disputed.
Accuracy of field tests: Field drug tests used by officers at the scene are known for producing false positives. Challenging the validity of these initial tests can weaken the case against you.
Laboratory procedures: Errors in laboratory testing, such as improper calibration of equipment or contamination of samples, can call the results into question.
Qualifications of analysts: The qualifications and credibility of the lab technician who performed the test can also be scrutinized. In some cases, testimony from an independent professional may be used to refute the prosecution’s evidence.
Challenging Witness Testimony
Witnesses play a significant role in many drug crime cases, whether they’re law enforcement officers, informants, or others involved in the alleged offense. Challenging the credibility and reliability of these witnesses can be a powerful defense strategy.
Bias or motive: Informants or co-defendants may have a motive to provide false or exaggerated testimony, such as leniency in their own cases. Highlighting these motives can undermine their credibility.
Inconsistencies: Any inconsistencies or contradictions in a witness's statements can be used to cast doubt on their testimony.
Procedural misconduct: If law enforcement witnesses fail to follow proper procedures during the investigation, their testimony may be questioned.
Cross-examining witnesses effectively is a crucial part of this process, and it requires a strategic approach tailored to the specific details of the case. A criminal defense lawyer is instrumental here.
Entrapment as a Defense
In certain situations, defendants may argue that they were induced or pressured by law enforcement to commit a crime they wouldn’t have otherwise committed. This is known as the entrapment defense.
Missouri law recognizes entrapment as a valid defense if it can be shown that:
The idea for the crime originated with law enforcement.
The defendant was persuaded or coerced into committing the crime.
Entrapment defenses often rely on presenting evidence of undue influence or coercion by law enforcement officers or informants.
Procedural Errors and Constitutional Violations
Procedural errors and violations of constitutional rights can significantly impact the admissibility of evidence. Examples include:
Failure to read Miranda rights: If you weren’t informed of your right to remain silent and your right to an attorney before being interrogated, statements made during that interrogation may be inadmissible.
Coerced confessions: Any confession obtained through intimidation, threats, or physical force can be challenged as a violation of your rights.
Right to legal representation: If you were denied access to legal counsel during critical stages of the investigation, it could affect the validity of the evidence collected.
Building a Strong Defense
Challenging evidence requires thorough preparation and a deep understanding of Missouri law. Every case is unique, and the defense strategy must be tailored to the specific facts and circumstances.
By identifying weaknesses in the prosecution's case and questioning the admissibility or reliability of evidence, you can create opportunities for a favorable outcome.
A criminal defense lawyer will review all aspects of your case, from the legality of the investigation to the credibility of the evidence. This process involves gathering relevant documentation, interviewing witnesses, and consulting with professionals when necessary.
Improper Use of Informants
Informants often play a role in drug crime cases, providing law enforcement with information or acting as intermediaries in controlled buys. While their testimony or actions can be central to the prosecution’s case, informants aren’t always reliable sources of evidence.
Their motivations, methods, and credibility can be challenged in several ways.
Questionable motives: Informants are often incentivized to provide information in exchange for reduced sentences, dropped charges, or monetary compensation. These motivations may lead to exaggerated or false statements.
Unethical conduct: Some informants may act improperly or entrap individuals into committing crimes. Evidence obtained through such actions may be inadmissible.
Lack of credibility: Highlighting an informant’s criminal record, history of dishonesty, or inconsistent statements can undermine their testimony.
Challenging the role of informants in a drug crime case can significantly weaken the prosecution’s argument, especially if their information is critical to obtaining evidence.
Issues With Surveillance Methods
Surveillance often plays a role in gathering evidence for drug crime cases. However, the methods used by law enforcement must comply with legal standards to confirm the rights of the accused aren’t violated. Defendants and a criminal defense lawyer can challenge surveillance evidence in several ways:
Unauthorized wiretapping: Wiretaps require a court order, and any conversations recorded without proper authorization may be inadmissible.
Use of GPS tracking devices: Law enforcement must obtain a warrant to use GPS devices to track a suspect’s movements. Evidence obtained without a valid warrant can be challenged.
Video surveillance: Cameras placed in private areas, such as a home or business, without permission or a warrant may violate the defendant’s constitutional rights.
By questioning the legality of surveillance methods, a criminal defense attorney can argue for the exclusion of evidence obtained through improper means.
Challenging Drug Quantity and Classification
The classification and quantity of drugs involved in a case often influence the severity of charges and potential penalties. In Missouri, drug crimes are categorized by the type of substance and its weight, following guidelines set by both state and federal law.
Defendants can challenge the prosecution's claims about drug classification and quantity in several ways:
Misidentification of the substance: Lab tests must confirm the substance is an illegal drug. Errors in testing or sample contamination can lead to misidentification.
Incorrect weight calculations: Prosecutors often rely on the total weight of drugs, including packaging. Challenging how the weight was calculated can reduce the charges or penalties.
Mixture or purity: Some cases involve mixtures containing illegal substances. Questioning the purity of the drug can affect the classification and potential sentencing.
By focusing on inaccuracies in the classification or weight of drugs, a defense strategy can reduce the severity of the charges or even lead to their dismissal.
Addressing Pretrial Publicity
High-profile drug crime cases sometimes attract media attention, which can prejudice potential jurors and influence the fairness of the trial. Missouri courts recognize the importance of impartiality in the judicial process, and defendants have the right to challenge any factors that may compromise a fair trial.
Steps to address pretrial publicity include:
Requesting a change of venue: If media coverage is likely to influence jurors, the defense can ask for the trial to be moved to a different jurisdiction.
Sequestering the jury: In some cases, isolating jurors from outside influences during the trial may be necessary.
Challenging biased jurors: During jury selection, the defense can question potential jurors and remove those with preconceived notions about the case.
Addressing pretrial publicity is critical for securing an impartial jury and a fair trial.
The Next Steps
At Walker Law, you’ll find an experienced and dedicated criminal defense lawyer: me. I serve St. Louis County and St. Charles County here in Missouri and the surrounding towns of Chesterfield and Cottleville. Contact my firm today.