Tampering with evidence involves destroying items to interfere with an investigation. Learn the penalties and how a criminal defense lawyer can help.
Tampering with evidence is a serious criminal offense under both federal and state laws. At its core, it involves altering, concealing, falsifying, or destroying physical or digital items to interfere with an official investigation or court proceeding. From a suspect tossing a weapon into a river to an executive shredding incriminating financial documents, the justice system punishes actions designed to obstruct the truth.
What Is Tampering With Evidence?
A person commits the federal crime of tampering with evidence when they knowingly alter, conceal, falsify, or destroy any record, document, or tangible object with the intent to interfere with an investigation, possible investigation, or other proceedings by the federal government. (18 U.S.C. § 1519 (2026).)
State laws also make it a crime to tamper with evidence in official proceedings and investigations. California's tampering law prohibits willfully destroying, erasing, or concealing any object, image, record, or other item that's considered evidence in a trial, inquiry, or investigation. (Cal. Penal Code § 135 (2026).)
What Are the Elements of a Tampering Crime?
Prosecutors must prove every element of tampering beyond a reasonable doubt to secure a conviction.
Must Be Evidence
When a person intentionally destroys a document or item that is not, and will not, become evidence in an investigation or other proceeding, there is no tampering with evidence. If someone flushes baking soda down the toilet thinking it's cocaine, they haven't tampered with evidence. Even though the person believed the substance was cocaine and intended to destroy evidence of that, this belief doesn't change the fact that there is no evidence of a crime.
Act Knowingly
In order to convict a person of tampering with evidence, a prosecutor must prove that the person knew that the item was evidence (or could be evidence) in an ongoing or future investigation or proceeding. For example, if a janitor feeds a stack of documents into the shredder, the janitor probably hasn't knowingly tampered with evidence, even if the stack included a document that showed the business was a money-laundering operation for a criminal syndicate. However, if the boss shredded that same document, it's far more likely that the boss acted knowingly.
Intentional or Knowing Interference or Tampering
A prosecutor must also prove that the individual charged with tampering with evidence intended to interfere with an investigation or other governmental proceeding when altering or destroying the evidence. So, it's not tampering if an incriminating document gets destroyed accidentally. Let's say the syndicate boss unintentionally knocks over a cappuccino onto incriminating accounting records, making them illegible. The boss hasn't knowingly altered the evidence.
Is It a Crime to Tamper With Evidence in Contemplation of a Future Proceeding?
A person who destroys evidence out of fear of an investigation or before a crime has been committed, intending to hide a later crime, has tampered with evidence. For example, the man who gets his wife drunk before leading her to the pool to kill her in a staged accident, but stops on the way to the diving board to wipe clean her lipstick from the whiskey glass, has tampered with evidence (in addition to committing murder). And, the inside stock trader who deletes emails to their source in order to leave no trail of illegal stock tips has destroyed evidence despite not being under investigation at the time.
What Are Common Defenses to Tampering With Evidence?
As with most crimes, there are several defenses that a person charged with tampering with evidence could raise. Here are a few of them.
Lack of Knowledge
An individual who can show that they lacked knowledge that a damaged or destroyed piece of evidence was, in fact, evidence will be acquitted. If the janitor in the example above can show that they only worked at night, had no contact with the people in the offices, did not know what business they were in, and had no information about their illegal activities, there can be no conviction.
Lack of Intent
Even one who destroys or alters a piece of evidence but who did not intend to interfere with a governmental investigation or proceeding has not tampered with evidence. If someone destroys evidence to prevent a colleague from seeing it (and not to interfere with an investigation), they didn't have the requisite intent for tampering.
How Is Tampering with Evidence Punished?
The U.S. government takes tampering with evidence very seriously. A person who is convicted of the crime under federal law can face a prison sentence of not more than 20 years, a fine, or both. (18 U.S.C. § 1519.)
State penalties vary. Some states make any tampering with evidence a felony offense. Other states make it a felony to tamper with a felony investigation or case and a misdemeanor to tamper with less serious cases. In California, the offense is a misdemeanor.
Consult With an Attorney
Talk to a lawyer experienced in criminal law if you have questions regarding a crime or investigation. If you can't afford an attorney, ask the judge for a public defender.
