S. 69 :Unexplained investments -Addition for alleged “on-money” paid for purchase of jewellery solely on the basis of statement of third party and documents found in search of another person, without any incriminating material found in assessee’s search and without corroboration, is unsustainable – Assessee cannot be asked to prove a negative – Addition cannot be made merely on conjectures and surmises. [ S. 132, 132(4), 153A ]