delivered the opinion of the Court.

A representative of the Department of Labor issued a subpoena requiring the defendant-employer to produce before him the payrolls for his business for a specific period covering two of his employees and the receipts he claims to have from these employees showing full payment of their salaries for the period in question. The defendant refused to produce the documents. On petition of the Commissioner, after a hearing thereon, the district court entered an order requiring the defendant under pain of contempt to comply with the subpoena of the Commissioner. The defendant has appealed from the order of the district court.1

The appellant assigns two errors. First, the lower court could not enter such an order “without any complaint existing against the defendant”. Second, § 5 of Act No. 15, Laws of Puerto Rico, 1931, as amended by Act No. 24, Laws of Puerto Rico, 1949, First Special Session, is unconstitutional insofar as it obliges an employer to deliver to the Commissioner of Labor documents which are defense evidence before a complaint is filed. In their briefs both parties argue the two errors together.

In the instant case both employees actually made oral complaints to the Department of Labor. The appellant therefore confines his contention with reference to the first error to the point that he has a right to know the terms of the complaint and that he cannot be compelled to produce *161the documents until he has been informed thereof in writing. We do not agree. It is true that § 5 imposes on the Commissioner the duty of investigating complaints of this nature. But even if there be no complaint at all, § 5 also requires the Commissioner to make the appropriate investigation when he may have reason to believe that a law protecting labor is being violated.2 Since the appellant could be compelled to produce his books even without a complaint, there is no basis for his contention that he is entitled to the details in writing of a complaint before he can be required to produce his records. Okla. Press Pub. Co. v. Walling, 327 U. S. 186.3

*162As to the second error, the appellant’s brief contains no discussion of the issue of constitutionality. We could therefore dispose of the case without any discussion of this point. In any event, the matter has been clearly settled by the Oklahoma Press Publishing Company case, which upheld a similar Federal statute, ruling that such powers of investigation and subpoena on the part of the Federal Administrator are equal to those of a grand jury, and that the exercise thereof is governed by the same limitations, which do not include any requirement that a complaint must be filed before an employer can be compelled to produce his records. See also, Interstate Commerce Comm. v. Brimson, 154 U. S. 447.

Although he does not assign a specific error with reference thereto, the appellant also makes the point that his records had already been previously examined by an investigator of the Department of Labor. The Commissioner argues on the contrary that the record shows merely that the investigator visited the defendant by virtue of a “friendly invitation”, but no examination or investigation was made in vthe real sense of those terms. We see no purpose in discussing this point. Even assuming the books have already been previously examined by the investigator, § 5 clearly contemplates that, for reasons of administrative convenience, the employer may be required to produce them in the *163offices of the Department, provided always, as the Commissioner concedes, the order is not unreasonable or oppressive and adequate precautions are taken to prevent their loss or mutilation. Okla. Press Pub. Co. v. Walling, supra, pp. 216-18.

The order of the district court will be affirmed.