Income - Assessee purchasing building and letting it out to its sister concern - Later on by book entry assessee showing to have sold the building to its sister concern and showing sale price as loan advanced to it on which interest was payable to assessee - Income-tax Officer disallowing transfer holding assessee as owner of building and adding house property income in total income of assessee - However, he also added interest payable on the sale consideration for the building - Held, order of Income-tax Officer was invalid - Once sale of building by assessee was disregarded no interest on sale price could accrue to the assessee. Income-tax Act (43 of 1961) , S.4, S.5— (Para 4)