A person with a bank account writes a bad check (also known as a non-sufficient funds or NSF check) when he deliberately or with knowledge writes a check for an amount of funds he knows are not available in the account. The crime of writing a bad check may also occur when a person writes a check on an account that has been closed. Another bad check scheme that may result in criminal charges occurs when an account holder writes a check for an amount in excess of the funds in the account, and deposits the check in a second account (often at a different bank)—and then withdraws the funds from the second account before the check is presented to the first bank for payment.

Bad check laws vary from state to state, and are usually located in the state’s penal or criminal code (statutes). Banks and criminal prosecutors recognize that a person can inadvertently write a check for more than the funds on deposit in their account, and not every instance will result in criminal charges. But many state laws have an expansive definition of the required knowledge or deliberate intent to write a bad check, and a criminal prosecutor does not have to prove a defendant charged with a bad check offense knew exactly how much money was in the account when the defendant wrote the check to prove the defendant knew he was writing a bad check or deliberately wrote a bad check.

In Missouri, writing a bad check, also known as writing a check with non-sufficient funds (NSF), is considered a criminal offense under Missouri Revised Statutes, specifically Section 570.120. A person commits the offense if they knowingly issue a check or other payment instrument, without sufficient funds or credit with the bank or other depository, to pay the check or instrument. This includes writing checks on an account that has been closed or writing a check for more funds than are in the account and then withdrawing the funds from a second account before the check clears. The severity of the offense can range from a misdemeanor to a felony, depending on the amount of the check and the circumstances. Missouri law recognizes that mistakes can happen, but the statute provides that the mere fact of a check being returned for insufficient funds is prima facie evidence of the issuer's knowledge of insufficient funds, unless they pay the holder the amount due within ten days after receiving notice of the insufficient funds. This means that while not every NSF check will lead to criminal charges, the law allows for the presumption that the issuer knew there were not enough funds, which can be used by prosecutors in building a case.