If you ever watched a movie or tv show you are aware of some common methods a scammer might use to commit fraud with a stolen check:
Altering information on a check: A scammer may use common household chemicals to change the printed dollar amount and payee name on a check. This is sometimes called “check washing.”
Forging endorsements and engaging in identity theft: Checks typically include name and address information on them, and criminals may use that information to steal someone’s identity. A fraudster may even attempt to open a bank account to negotiate the check payable to the intended payee by forging the endorsement and then go on to leverage that stolen identity to apply for credit products using the victims’ personal information.
Creating counterfeit or duplicate checks: By using the information on the stolen check, fraudsters may further exploit the victim’s account information by creating additional counterfeit copies of the check.