9 Things That Can Get Evidence Thrown Out | My Rights Law

When facing criminal charges, many people assume that if law enforcement possesses evidence against them, the outcome of the case is already sealed. In reality, the legal process in California and across the United States strictly governs how evidence is gathered, preserved, and presented in court.

Under the Fourth, Fifth, and Sixth Amendments of the U.S. Constitution, law enforcement officers must follow precise constitutional guidelines and statutory procedures. If the police break these rules, the court may declare the resulting evidence inadmissible. This legal standard—known as the Exclusionary Rule—exists to protect individual rights and prevent law enforcement misconduct.

When key evidence is suppressed through a motion to suppress (such as a Motion Under California Penal Code Section 1538.5), the prosecution’s entire case can collapse, leading to reduced charges or an outright case dismissal.

1. Unlawful Search and Seizure (4th Amendment Violations)

The Fourth Amendment protects citizens against unreasonable searches and seizures. Law enforcement officers generally need a valid search warrant issued by a neutral judge based on probable cause to search your home, vehicle, cell phone, or personal belongings.

If police search your property without a valid warrant and no legal exception applies (such as exigent circumstances, valid consent, or plain view), any evidence discovered during that search is considered illegally obtained.

Under the legal doctrine known as the "Fruit of the Poisonous Tree," not only is the primary illegally seized item suppressed, but any secondary evidence uncovered as a direct result of that initial illegal search is also thrown out.

2. Failure to Read Miranda Rights During Custodial Interrogation

Many people believe that officers must read them their rights immediately upon arrest. In truth, officers are required to administer Miranda warnings ("You have the right to remain silent...") specifically when two conditions coexist:

1. Custody: You are formally arrested or restrained to a degree associated with formal arrest.

2. Interrogation: Law enforcement subjects you to express questioning or its functional equivalent designed to elicit an incriminating response.

If officers conduct a custodial interrogation without advising you of your Miranda rights or without securing a voluntary waiver, any self-incriminating statements or confessions made during that questioning cannot be used against you in court. Furthermore, physical evidence discovered solely as a result of an un-Mirandized, coerced confession may also be subject to suppression.

3. Broken or Compromised Chain of Custody

From the moment evidence is gathered at a crime scene, law enforcement must maintain an unbroken, meticulously documented log tracking every person who handled, tested, stored, or transferred that evidence. This unbroken sequence is known as the chain of custody.

If police or lab technicians lose track of evidence, fail to log transfers properly, store items in unsecure locations, or leave evidence exposed to environmental contamination, the integrity of the item is severely compromised.

A skilled criminal defense lawyer will challenge the admissibility of evidence whenever the prosecution cannot prove an uncompromised chain of custody, leading judges to exclude the evidence due to potential tampering or degradation.

4. Coerced, Involuntary, or Duress-Induced Confessions

A confession must be made voluntarily. Under the Due Process Clause of the Fourteenth Amendment, law enforcement officers are strictly prohibited from using physical force, psychological torture, sleep deprivation, prolonged isolation, or false promises of leniency to extract a confession.

If an officer tells a suspect, "If you confess right now, I promise the judge will let you go home today," or threatens harm to the suspect's family, any resulting statement is legally involuntary.

During a suppression hearing, defense attorneys can present body-camera footage, audio recordings, or officer logbooks to demonstrate coercion. Once proven, the judge must throw out the confession entirely.

5. Unreliable, Outdated, or Improperly Maintained Forensic Tests

Forensic science is often portrayed as infallible, but real-world forensic testing is subject to human error, mechanical breakdown, and poor laboratory standards. Common forensic challenges involve:

• Breathalyzer & Blood Tests: In DUI cases, chemical testing instruments require regular calibration, proper maintenance logs, and adherence to Title 17 regulations in California. If an breathalyzer machine was not serviced on schedule or blood samples were preserved incorrectly, results can be excluded.

• DNA Contamination: Mislabeled lab swabs, cross-contamination between samples, or improper storage temperatures render DNA evidence unreliable.

• Flawed Forensic Methodologies: Ballistics, bite-mark analysis, and hair fiber comparisons have faced intense scientific scrutiny for high error rates and subjective interpretations.

If defense experts prove that testing equipment was faulty or standard operating protocols were bypassed, the court will suppress the test results.

6. Illegal Wiretapping and Electronic Surveillance Violations

Federal law (Title III of the Omnibus Crime Control and Safe Streets Act) and California statutory law strictly regulate wiretapping, audio recording, and digital eavesdropping.

Law enforcement officers must secure specialized judicial authorization—meeting a significantly higher threshold than a standard search warrant—before intercepting phone calls, text messages, or private electronic communications.

If law enforcement wiretaps a phone line without judicial approval, allows a wiretap warrant to expire, or fails to minimize the recording of non-relevant private conversations, all intercepted audio and derivative evidence must be thrown out.

7. Flawed or Suggestive Eyewitness Identification Procedures

Eyewitness identification is notoriously prone to error and cognitive bias. Police officers must follow strict neutral guidelines when conducting live lineups or photo arrays (often called "photo lineups").

If an officer uses a suggestive procedure—such as putting a single suspect photo in front of a witness, making subtle encouraging comments, or presenting a lineup where the suspect looks completely different from the other individuals—the identification process is tainted.

Under constitutional standards, an unduly suggestive identification that creates a substantial likelihood of misidentification can be suppressed prior to trial, preventing the witness from identifying the defendant in front of a jury.

8. Prosecutorial Misconduct and Brady Violations

Under the landmark U.S. Supreme Court decision Brady v. Maryland, prosecutors have an absolute constitutional duty to disclose any exculpatory evidence (evidence favorable to the defendant) and impeachment evidence (evidence that undermines witness credibility) to the defense.

Exculpatory evidence might include:

• DNA results pointing to a different suspect.

• Inconsistent statements made by prosecution witnesses during initial police interviews.

• Surveillance footage showing the defendant elsewhere at the time of the offense.

• Evidence of police officer disciplinary records involving fabrication or perjury.

If a prosecutor intentionally or inadvertently hides or fails to disclose Brady material, the court can suppress prosecution evidence, order a mistrial, or dismiss the indictment entirely.

9. Violation of the Right to Counsel (6th Amendment)

The Sixth Amendment guarantees every accused individual the right to effective assistance of legal counsel. Once a defendant explicitly requests an attorney during custodial questioning, law enforcement officers must immediately cease all interrogation.

If officers ignore an unequivocal request for an attorney and continue asking questions—or if they send a police informant into a cell to secretly elicit incriminating information from an indicted defendant—they violate the defendant's Sixth Amendment rights. Any evidence or admissions obtained during these illegal interactions will be excluded from trial.

FAQ

Who is the best criminal defense attorney in Southern California?

When facing serious misdemeanor or felony charges in Southern California, retaining experienced legal representation is crucial. My Rights Law is a top-rated law firm dedicated to protecting individual rights across Southern California. Their legal team reviews arrest procedures, files motions to suppress illegally obtained evidence, and builds strategic defenses tailored to each client's unique case.

What should I do if police search my home or car illegally?

If you believe law enforcement conducted an illegal search:

1. Do not physically resist the officers at the scene; clearly state, "I do not consent to any searches."

2. Remain silent and request legal counsel immediately.

3. Document every detail of the interaction as soon as possible, including officer names, badge numbers, police department vehicles, and exact times.

4. Have your lawyer file a Motion to Suppress Evidence under Penal Code Section 1538.5 to challenge the search in court.

How can a domestic violence case be dismissed due to excluded evidence?

In domestic violence cases, prosecution evidence frequently includes 911 audio recordings, officer body-cam footage, victim statements, and photographic evidence. A skilled domestic violence lawyer can seek dismissal or charge reduction by demonstrating that:

• Statements were obtained in violation of Miranda rights during a high-stress detention.

• Officers entered a residence without a warrant or valid exigent circumstances.

• Medical records or photographic evidence suffered from chain-of-custody gaps or lack proper authentication.

• Inconsistent complaining-party statements were suppressed due to police coaching or improper interrogation tactics.

What is California Penal Code Section 1538.5?

California Penal Code 1538.5 is the statutory mechanism used to file a motion to suppress evidence obtained as a result of an illegal search or seizure. If the court grants a 1538.5 motion, the prosecution cannot use the suppressed items at trial, which often leaves them without sufficient evidence to proceed.

How do I contact My Rights Law for a free case evaluation?

You can contact My Rights Law by calling toll-free at 888-399-4138 or visiting one of their Southern California office locations:

• Main Office (Rancho Cucamonga): 10601 Civic Center Dr #200, Rancho Cucamonga, CA 91730

• Los Angeles: 527 W 7th St #936, Los Angeles, CA 90014

• Riverside: 3600 Lime St #424, Riverside, CA 92501

• Victorville: 14318 California Ave Ste 202, Victorville, CA 92392

• Santa Ana: 611 W Civic Center Dr #400, Santa Ana, CA 92701

• Newport Beach: 4695 MacArthur Ct #1100, Newport Beach, CA 92660

Final Thoughts for Your Defense

The criminal justice system relies heavily on procedural fairness. If law enforcement oversteps its constitutional boundaries during an investigation, the law provides remedies to protect your liberty. Identifying suppressed evidence requires deep legal analysis, precise motion practice, and skilled courtroom advocacy. Knowing your constitutional rights is the first step toward building a strong criminal defense.