It shall not be necessary for the informant to give the individual names of tenants in common, co-tenants, joint tenants, or partnerships, nor their individual interests, where the same are unknown; but the same shall escheat in the name by which their joint interests were or are held: Provided, That where such names or interests are not known, affidavit to that effect shall be made by the informant, and filed of record.
27 P.S. § 11