The AO has made the addition as some of the suppliers of the assessee were declared Hawala dealer by the Sales tax Department. This may be a good reason for making further investigation but the AO did not make any further investigation and merely completed the assessment on suspicion. Once the assessee has brought on record the details of payments by account payee cheque, it was incumbent on the AO to have verified the payment details from the bank of the assessee and also from the bank of the suppliers to verify whether there was any immediate cash withdrawal from their account