The owner or any person having an interest in or encumbrance on any piece of property may, at any time at least three months before the last day of the redemption period, file in the office of the clerk of said court a bona fide defense, verified under oath, in duplicate, to the proceeding in respect to such property, identifying the same by its serial number, and, if the court is satisfied that the defense stated is a bona fide defense, it shall direct the clerk to write opposite the description of the property in the list the word “Withdrawn”, and thereafter such property shall not be within the scope of the proceeding.