Section 48. Upon complaint signed and sworn to by a registered voter and filed with the registrars at least fourteen days in a city, or at least four days in a town, before a primary, election or town meeting, stating that the complainant has reason to believe and does believe that a certain person by him therein named has been illegally or incorrectly registered, and giving the reasons for such belief, the registrars shall examine into such complaint and, if satisfied that there is sufficient ground therefor, they shall summon the person complained of to appear before them at a certain place and time before the next primary or election or town meeting to answer to the matters set forth in the complaint, and the substance of the complaint and a copy of this section and of section forty-nine shall be set forth in the summons. Service of the summons shall be made by an officer qualified to serve civil or criminal process, not more than fourteen nor less than two days before the day named for appearance, by delivering in hand a copy of the summons to the person therein named, or by leaving it at his place of residence, or, if personal service cannot be made and the person’s residence is unknown to the officer and cannot be ascertained by inquiry at the place of alleged illegal or incorrect residence or at any later residence of such person appearing on the register, then at such person’s last residence, if any, known to the officer, or, if the person’s last residence is unknown, at the last place appearing as his residence in the register. The officer shall return the summons to the registrars before the day named for appearance with the certificate of his doings endorsed thereon.