Section 4. If, in case of a supposed escheat, no person appears as the heir of the person last seized, or if in any case there is reason to suppose that there is a person claiming an estate or interest in the land, whose name is unknown, who is absent from the commonwealth or who cannot be found therein to be served with process, the court shall, in addition to any other service, order the substance of the complaint with the order of the court thereon to be published once in each of three successive weeks in a newspaper designated by it, the first publication to be at least ninety days before the time appointed for the appearance of the parties.