If you arrested for a perjury crime, you are basically charged with lying. You can be charged with perjury if: You lie to a federal or state grand jury in a civil or criminal case; You lie to police during an investigation; You lie under oath during testimony; You falsify government documents or information. Perjury is a hard crime to prosecute. Other crimes that are similar include “lying under oath” and false swearing. Prosecutors have to show that the offender knew that he or she was lying to convict an offender. Common defenses for perjury crimes include: “I didn’t’ understand the question.”; “I didn’t remember.”; “It happened so long ago I am not sure what happened.”; “I was traumatized and didn’t realize what I was saying.” If a person is convicted, he or she will most likely spend time in prison. Sentences average to one to five years behind bars.