If the citation be returned unexecuted because such fiduciary cannot be found after diligent search by the sheriff to whom it is directed, then the clerk shall make and file among the papers in the cause an affidavit stating such information as he may have been able to ascertain after diligent inquiry concerning the whereabouts and post office address of such fiduciary. If by such affidavit it shall appear that the whereabouts of such fiduciary is unknown to the clerk or that he is a nonresident of, or absents himself from, this state, then the court or chancellor shall make an order directing the issuance and publication of an alias citation for such fiduciary to appear and show cause why he should not be removed, at a time and place specified therein, not less than thirty days from the date of such order. The sheriff of the county where such matter or cause is pending shall thereupon make publication of such citation by posting a true copy thereof at three public places in his county, one of which shall be at the courthouse, not less than twenty-one days before the return day thereof, and shall make return of the citation showing such publication and the date and places where such copies were posted. If the clerk’s affidavit shall show the post office address of such fiduciary, then the clerk shall, at the time of issuing such alias citation for publication, mail postage prepaid a true copy thereof to him at such address and note the fact on his general docket in the same manner and with the same effect as in other like cases. On the return of such alias citation, executed by publication as aforesaid, the court or chancellor shall be as fully empowered to proceed as if such fiduciary had been personally served in this state.