fbi weird situation

Today the FBI came to the door looking for my husband and he wasn't home so I gave them his number and they called him and had him come to their office and talk with them . They asked him some questions about him writing his cousin a check and his cousin writing him one in the past as well. At the end the officer told him they were looking for something bigger and will turn the case over to the attorney general . What does this mean? We still are unsure on what is going on