INVESTIGATION. – Inquiry to be conducted prior to the celebration of Marriage and the conferral of Orders, in order to ascertain the existence of the requirements prescribed by law and the absence of impediments or irregularities. This investigation is administrative in character, distinct from the judicial form; in fact, it is not followed by a judgment, but by authorization to proceed, or by a prohibition.
I. PRELIMINARY INVESTIGATION FOR MARRIAGE
More common and part of daily practice is the investigation that precedes Marriage, also called the “marriage inquiry process.”This investigation, prescribed by the CIC (canons 1019 and 1020), is necessary so that the sacrament of Marriage may not be exposed to nullity or profanation. It must establish whether the two contracting parties have been validly baptized and enjoy freedom of status, and more generally whether anything stands in the way of the valid and licit celebration of Marriage; otherwise, it may not take place.
(from V. Lorequais, Les bréviaires mes. des Bibl. publ. de France, Paris 1914, plate 21)
INVENZIONE DELLA S. CROCE - S. Elena assiste alla I. della s. C. (in alto); prova della verità della s. C. (in basso). Miniatures of the Belleville Breviary (first half of the fourteenth century) - Paris, National Library, ms. lat. 10.483, f. 178.

Legal proof both of Baptism and of free status is obtained by means of documents, interrogations, and banns.
The documents to be examined are the parish registers, the Baptismal certificates of the parties, that of the Marriage of their parents, and also, when necessary, the death certificate of a previous spouse if one of them were a widower or widow, the sentence of nullity or the dispensation if the previous Marriage of one of them had been declared null or dispensed from because it had not been consummated.
The first to be interrogated are the parties, followed by witnesses for each of them—relatives or acquaintances, of unimpeachable character in the judgment of the parish priest—who can testify with certainty regarding the information requested of them. There must be at least two witnesses for each of the betrothed, therefore four in all; but there may also be only two, provided that they testify for both. There is a special form for this interrogation, to which variations or additions may be made according to the circumstances.
These investigations (documents and interrogations) should reveal, if it really exists, some impediment, especially if public, for which, when there are just causes, a dispensation must be requested in advance.
For greater assurance of freedom of status, the banns of the proposed Marriage are prescribed. These may be published either by means of a notice posted on the door of the parish church, or orally, that is, read by the parish priest during a service attended by the people. The notices must remain posted for at least eight days and include at least two days of precept; the oral banns must be published on three consecutive Sundays or feast days. In urgent cases or particular circumstances, however, partial or total dispensation from this rule may be obtained, provided that freedom of status emerges from other evidence. The banns have legal validity for six months. The faithful who know of the existence of an impediment to a particular Marriage have the duty, even independently of the banns, to report it to the parish priest or the Ordinary, unless they have been dispensed from this obligation.
For the premarital investigation to achieve the effect intended by law, it must also concern the will of the parties, since the validity of the Sacrament depends as well on the free expression of consent. For this purpose, in the interrogation the betrothed, as well as the witnesses, must answer whether they are freely giving their consent, or whether this consent is vitiated or conditional. There are, in fact, intentions or conditions that render the Marriage null, either because they remove the freedom of the act, or because they impair the so-called essential goods of Marriage: the good of offspring, the good of fidelity (unity), and the good of the Sacrament (indissolubility). When such cases arise, if the parish priest does not obtain the retraction of these intentions or conditions, he must refuse to assist at the Marriage, which would be null or at least illicit.
Accordingly, whether the parish priest may proceed to celebrate the Marriage, or whether he must have recourse to the Ordinary for the necessary possible dispensation or for the “authorization to proceed,” depends on the results of the investigation. The cases in which recourse to the Ordinary is necessary are those established by the CIC or by the special “instructions,” and also those in which a required document is lacking or there is some doubt concerning the Baptism or freedom of status of either party. Doubt concerning Baptism can be remedied by administering the Sacrament sub conditione, or, in the event of refusal, by a dispensation from doubtful disparity of worship. To ascertain freedom of status, banns must also be published in other places where the party may have been able to contract another bond; or, in the case of a previous Marriage, inquiries must be conducted into the death of the spouse. Often, for greater assurance, the betrothed are asked to make the so-called supplementary oath, which is prescribed only when the evidence is not completely certain. At the point of death, for the celebration of the Marriage it is sufficient that the parties swear that they are baptized and free of any bond, provided that nothing to the contrary emerges.
In places where religious Marriage has civil effects by concordat, other prescribed documents must be added to the marriage file. Finally, once the Marriage has been celebrated, the entire dossier containing the investigation is kept in the archive of the parish where it was drawn up, or in another place established by diocesan regulations.
II. PRELIMINARY INVESTIGATION PRIOR TO THE CONFERRAL OF THE SACRAMENT OF ORDER
The nobility and divine powers which the sacrament of Order confers upon man require that the candidate be worthy, suitable, and capable of fulfilling his mission in the world in a decorous and fruitful manner. The Church is concerned with this and seeks to obtain a guarantee in advance.From the beginning, it is forbidden to admit to seminaries young men who certainly do not have a vocation. It is likewise necessary to ascertain beforehand whether the candidate is affected by the so-called irregularities (v.), or held back by a simple impediment (v.).
Although candidates for the priesthood are definitively incorporated into the clergy only with the reception of the subdiaconate, the i. with a view to the future priesthood is nevertheless begun carefully from the time of the first tonsure.
Its principal object is the candidate’s vocation to the priestly dignity, in the broadest sense of the word: all the elements from which this vocation may become clear must therefore be considered; it is not merely the call of a superior, even if he is the bishop. Accordingly, the so-called scrutiny is prescribed, from which should emerge the candidate’s will to assume consciously the burdens of the priesthood, his aptitudes, heartfelt piety, zeal, love of study, and absence of defects that might prejudice the priestly ministry. These indications or signs must be found positively and securely in the candidate, and may already be observed during the course of his studies.
When the time established for the reception of the tonsure approaches, the prescriptions concerning the scrutiny must be observed, unless certain information or findings reveal the person’s unworthiness, in which case he is dismissed outright. At least two months beforehand, the candidate must submit a written request to the rector of the seminary, who sends it to the bishop of the applicant, attaching the certificates of Baptism and Confirmation. The bishop returns the request to the rector, entrusting him with the task of investigating and reporting to him on the conduct, suitability, and qualities of the postulant, bearing in mind a form proposed by the S. Congregation of the Sacraments. He also requests information from the candidate’s parish priest, as well as from other persons who may be informed about his conduct and piety, his free will in receiving Orders, his morals and the other signs of his vocation, the esteem in which he is held, his public reputation, etc. He must also hear the opinion of the seminary’s disciplinary commission. Moreover, the bishop himself or, if he is impeded, a person appointed by him, must personally question the applicant in order to ascertain his freedom in receiving Holy Orders and his willingness to assume their burdens: for this purpose, what the Roman Pontifical says on the matter is to be read to him. Only in the event of a favorable outcome will the bishop decide to admit him.
This investigation must also be taken into consideration when the minor Orders are conferred. But it must be repeated, supplemented, brought up to date, and compared when promotion to the subdiaconate is concerned. For this Order, in addition to the information required, as was done for the first tonsure, the evidence provided afterward must be taken into account, and the candidate must answer and sign his declaration of freedom and awareness in receiving the Order, together with the obligations attached to II.
For the conferral of the diaconate, it is sufficient to refer to the previous i., except where new circumstances or some doubt have arisen concerning the vocation or suitability for observing the obligations. The same applies to admission to the priesthood. If the doubts are dispelled following a thorough investigation and serious examination, one may proceed further; otherwise, the bishop must have recourse to the Holy See, setting out the case in detail. The latter, having taken everything into consideration, will decide what action is to be taken.