(7)For the purpose of determining the amount-(a)the Collector shall have power to require any person to deliver to him such returns and assessments as he considers necessary;(b)the Collector shall also have power to require any person known or believed to be interested in the land to deliver to him a statement containing, as far as may be practicable, the name of every other person interested in the land as co-owner, mortgagee, tenant or otherwise, and the nature of such interest, and of the rents and profits, if any, received or receivable on account thereof for three years next preceding the date of the statement.
