Is it a crime to forge a letter of understanding in a criminal case? Hello, this is a bit serious. Submitting a forged letter of understanding may constitute the crime of forging evidence. According to the criminal law, anyone who commits the crime of forging evidence shall be sentenced to fixed-term imprisonment of not more than three years or criminal detention. Lawyer’s advice: Don’t take criminal cases lightly. The law is serious and you must seek truth from facts. Many times, others can make mistakes, but the person involved must not risk making mistakes, otherwise it may have a counterproductive effect on their loved ones in prison and make things worse. If you are the injured party, it is recommended to report the case to the case handling agency in time to avoid causing losses to the victim. Hope this helps.