paid checks returned for fraud

How long may a customer wait to file paperwork on their account if they feel there is fraud on the account and then what is the timeframe that paid checks on the account can be returned for fraud?

The answer will vary depending on the specific nature of the fraud (forged maker signature, forged endorsement, altered check, etc.). Can you provide more detail about the situation?

one will be altered check and one will be forged maker signature

Forged signature falls under your midnight of the 2nd day return deadline. You can file a without entry claim to the depositing bank for the altered check (I believe up to a year?)

Forged endorsement claims typically have a 3 year window to file (unless your state law dictates a shorter time period).