Tampering with evidence is a very serious offense that carries the possibility of lengthy jail time. Tampering with any type of evidence by destroying, altering or suppressing of falsifying evidence is typically rather difficult to prove, however these cases are often very successful prosecuted. Tampering differs from perjury in that it is not just a statement, it is the intentional altering, concealing, modifying or destruction of physical evidence in any form. This can include wiping out a hard drive, destroying letters or other evidence or removing objects or materials during or after a crime has been committed. The reasons why the individual moved, altered, concealed or destroyed the evidence are not relevant to the charges, however in most cases it is done to avoid implication or guilt. In some cases, like perjury charges, tampering with evidence may also include knowingly submitting or using falsified evidence in any type of court or legal procedure with intent to influence the outcome. Not knowing that the material or information was part of the investigation and would be considered evidence is not typically an effective defense as it is based on the reasonable assumption the information may be relevant to the case.