Last Updated on July 2, 2025
Evidence integrity in the court system is critical, especially as the US justice system requires prosecutors to prove the defendant’s guilt beyond a reasonable doubt. Unreliable or missing evidence could result in great injustices. To protect evidence accuracy, California has passed many laws prohibiting its destruction, concealment, or alteration. If you have been accused of any of these offenses, please call an attorney as soon as possible.
Table of Contents
- Preparing and Offering False Evidence: 134 & 132 (PC)
- Destruction or Concealment of Evidence: 135 (PC)
- Planting or Tampering With Evidence: 141 (PC)
- A Shocking Example of Evidence Tampering
- What Are the Penalties?
- Fighting the Charges
- Related charges
- Frequently Asked Questions
- Call a Lawyer as Soon as Possible
Preparing and Offering False Evidence: 134 & 132 (PC)
These two crimes are very similar, so they are frequently discussed simultaneously. However, they are uniquely distinct criminal actions. The distinction between the two charges lies in the defendant’s role in creating and introducing false evidence during an investigation.
Preparing false evidence, filed under Penal Code section 134 (PC), is the crime of creating a fraudulent document or other item with the intent to use it as evidence in a legal setting. Offering false evidence, filed under Penal Code section 132 (PC), occurs when someone knowingly presents a forged or altered piece of evidence to a court, investigator, or other legal agency or agency —for example, creating a fake concert ticket to provide you with an alibi for a crime.
You can also be charged with providing false evidence to wrongly accuse someone else of a crime. For example, if you edited a video to make it look like someone committed a crime and turned it into the police, you could be charged with preparing false evidence if the forgery was discovered.
Destruction or Concealment of Evidence: 135 (PC)
It’s understandable that someone accused of a crime would want to destroy evidence of their wrongdoing, but doing so can result in you facing even more criminal charges. Under 135 (PC), it is a crime to willfully destroy or conceal something you know may be used as evidence. You do not need to be the individual under criminal investigation —if you shred documents to protect someone else from prosecution, you can still be charged with destroying evidence.
Planting or Tampering With Evidence: 141 (PC)
Under California law, it is illegal to alter, modify, plant, place, manufacture, conceal, or move evidence to be used in a trial or other legal proceeding or with the intent of getting someone charged with a crime. While most people envision this law covering only physical evidence, it also covers analog and digital content. As a result, Photoshopping a person out of a photograph to help hide their guilt would still be illegal.
A Shocking Example of Evidence Tampering
While evidence tampering by those in the justice system is rare, it does happen, and the consequences can be far reaching. In one notable case, Massachusetts State Police chemist Annie Dookhan pleaded guilty to tampering with evidence after confessing that she cut corners on drug tests, improperly removed evidence from storage, forged signatures on documents, and recorded negative tests as positive. In addition, she lied about having a master’s in chemistry when applying for her job. Dookhan committed these acts for two to three years and was involved with over 40,000 criminal cases.
In a similar local case in 2009, the city contracted a third-party contractor to run over 500 tests. After they found no sign of inconsistencies from the original reports, the issue was dropped, and no prisoners were released, as it was determined the test results were accurate.
In a similar local case that took place in 2009, the city contracted a third-party contractor to run over 500 tests. After they found no sign of inconsistencies from the original reports, the issue was dropped and no prisoners were released, as it was determined the test results were accurate.
These scandals are an excellent reminder of why it always pays to have your lawyer retest and/or challenge a chemical sample if you disagree with the evidence presented by the prosecution. Remember that while forensic science can help law enforcement solve crimes, it is not infallible, particularly if those testing it or handling it may have tampered with the results.
What Are the Penalties?
Preparing or Offering False Evidence
No matter what kind of case, the type of evidence, or the seriousness of the issue, the penalties for these crimes are the same —up to three years in California state prison. That means that even if you manipulated evidence to fight a parking ticket, you could still receive the same penalty as someone who attempted to frame someone else for murder.
Destroying or Concealing Evidence
135 (PC) is a misdemeanor offense in California. The maximum sentence is up to six months in county jail and a fine of up to $1,000. If a criminal lawyer ever urges you to destroy or hide evidence, they are committing a crime, which could put your lawyer/client confidentiality at risk and jeopardize your criminal case. When this occurs, seek out new criminal defense attorneys as soon as possible to discuss your current legal situation and potential issues that could arise due to your prior lawyer’s unethical and illegal advice.
Planting or Tampering With Evidence
Ordinarily, this crime is a misdemeanor, punishable by up to 6 months in jail and a fine of up to $1,000. However, the crime becomes a felony punishable by up to five years in prison if the defendant is a law enforcement officer because peace officers are given so much more power and trust regarding the handling of evidence and investigation of a crime scene.
Fighting the Charges
Defenses for all of these offenses vary based on the specifics of your situation. Regardless of the charge, the prosecution must have sufficient proof to show beyond a reasonable doubt that the defendant knowingly and willingly broke the law. Examples of evidence-related issues that would not be crimes because the defendant lacked intent include:
- A husband accidentally presents a forged letter to the divorce court that he believes his wife actually wrote
- A police officer accidentally drops and smashes a plaster casting of a suspect’s footprint
- A secretary unknowingly shreds potentially damning paperwork that their boss placed in their office shred pile
- Someone plants a shirt with a potential suspect’s blood sample and fingerprints at the scene of a crime at the request of their friend, not knowing their friend is trying to frame their ex
- A person takes their mother’s stuff from a crime scene at mom’s request, not knowing it was to conceal evidence from the police
Proving intent and knowledge can be tricky unless you confess during the investigation. If you are charged with this crime or believe you may be accused, always speak with a lawyer before speaking to investigators. Police will do whatever they can to get suspects to confess during interrogations, and attorneys can protect you from saying or doing something that may hurt your case later.
Similarly, if you are accused of presenting false evidence but the prosecution cannot prove it was fraudulent, you are not guilty under the law.
When it comes to destroying evidence, prosecutors must show that you knew the object or objects in question are likely to be used as evidence. If you shred old business documents every few months, you cannot be charged with the crime simply for clearing out your old paperwork. However, an exception would be made if you intentionally included documents you knew could be used as a paper record of evidence against you in a case or investigation. Showing that potential evidence was damaged purposefully to prevent it from falling into investigators’ hands can be difficult for the prosecution, especially when you have a skilled defense lawyer.
Those charged with evidence-related crimes will likely face other offenses depending on their actions. Those who lie under oath or fraudulently fill out government documents may be accused of perjury. When someone falsifies documents presented to investigators or the courts, they could be charged with forgery. Alternatively, when someone falsely accuses another person of a crime, they could be charged with filing a false police report.
Frequently Asked Questions
Who Can be Charged With Tampering With Evidence?
Notably, while many people associate evidence only with criminal matters, these evidence laws also apply in civil courts. As a result, charges can also be filed against individuals involved in lawsuits, divorce hearings, child custody matters, immigration trials, and financial cases, such as bankruptcies. If someone forges a document in a small claims court and introduces it as evidence, they can still be charged with both preparing and offering false evidence —and possibly forgery and perjury as well.
Does the Destruction of Evidence Help a Case?
In many cases, destroying evidence proves fruitless because investigators find other ways to collect the proof they need or reconstruct it from any scraps you left behind.
For example, if you delete emails, they will likely still be on the email server or in the inbox of the person who sent or received the messages. Alternatively, if you shred documents with no other copies, a forensics team might be brought in to reassemble the paper shreds, which will still be used as evidence.
Modern technologies are making it increasingly challenging to permanently destroy potential evidence in a way that cannot be recovered later on. If you believe you are under investigation for any type of criminal offense, do not interfere with the evidence. Hiding evidence can also result in your facing criminal charges, so working with a defense attorney to build a strategy to fight the charges is more effective than committing this crime.
What’s the Difference Between Preparing Falsified Evidence and Planting or Tampering With Evidence?
Both charges are forms of obstruction of justice as they interfere with the investigation of crimes or court proceedings. While it is possible to violate both 134 and 141 (PC), most offenders are only charged with one or the other. Preparing evidence involves creating evidence from scratch. Planting evidence means placing already created evidence at the scene of a crime. Tampering with evidence consists in altering or moving evidence.
Call a Lawyer as Soon as Possible
If you have been accused of any of these crimes, a criminal defense attorney can help you develop a defense strategy before charges are even filed. You can schedule a free initial consultation with Peter M. Liss can help. Please call (760) 643-4050 or (858) 486-3024 to schedule a free consultation to discuss your case.