1. Since the Loan cheque was given in name of your Friend (Loan Taker), ONLY & ONLY the friend is liable for the same and NOT you, in any manner whatsoever.
2. The Loan-Giver Friend CANNOT prosecute you in any manner, whatsoever, specially for cheque bouncing cases, since you do not have legally enforceable liability /debt towards such friend, more specially so since the loan amount would be reflected in the income tax returns of the Loan-Giver Friend against Friend (Loan Taker) and NOT against your name.
3. Even IF a case is filed, THEN you have to simply say you have no legally enforceable liability /debt to the Loan-Giver Friend and that the said blank cheque was lost /misplaced from your office /residence.