If the department finds that a general relief allowance has been improperly granted, it shall investigate, and if it appears from the investigation that the assistance was improperly granted, the department may cancel the allowance and notify the recipient of the cancellation. The state then has a claim against the person who received the improper allowance. The claim may be enforced by civil action in the name of the state by the attorney general to recover the amount paid to the person, with interest, together with the necessary costs of the action.