Qua, C.J.

This petition for a writ of certiorari was brought in the Superior Court to quash a decision of the judge of the Municipal Court of the Roxbury District *572wherein he found that action of the police commissioner of Boston discharging the petitioner from the police force of that city, after a hearing upon two specifications of conduct unbecoming an ofiicer, and action of the civil service commission affirming the action of the police commissioner were justified, and whereby the respondent affirmed such action. G. L. (Ter. Ed.) c. 31, § 43, as appearing in St. 1945, c. 667, § 1 (see now St. 1947, c. 373, § 1). G. L. (Ter. Ed.) c. 31, § 45, as appearing in St. 1945, c. 667, § 2. The judge of the Superior Court ordered judgment affirming the proceedings before the respondent. G. L. (Ter. Ed.) c. 249, § 4, as amended by St. 1943, c. 374, § 1. See G. L. (Ter. Ed.) c. 213, § 1A, as last amended by St. 1941, c. 180. The case is here on exceptions to the refusal of the judge of the Superior Court to grant certain of the petitioner’s requests for rulings.

General Laws (Ter. Ed.) c. 31, § 43 (b), as appearing in St. 1945, c. 667, § 1, provides that a person discharged by the appointing authority shall, if he so requests in writing, be given a hearing before a member of the civil service commission or some disinterested person designated by the chairman, who shall report his findings to the commission for action. The commission is to affirm the action of the appointing authority if it finds that such action was “justified.” We interpret this as providing for a hearing de nova upon all material evidence and a decision by the commission upon that evidence and not merely for a review of the previous hearing held before the appointing officer. There is no limitation of the evidence to that which was before the appointing officer. The matter is still wholly in the administrative field. In this connection, we think that the word “justified” has no peculiar or technical signification. But the petition to the District Court which may be brought after the decision of the commission is, by the wording of G. L. (Ter. Ed.) c. 31, § 45, as appearing in St. 1945, c. 667, § 2, a petition for a review by the court of the action of the administrative officers to “determine whether or not upon all the evidence such action was justified.” The scope under a statute of this type of a judicial review to determine whether the action *573of an administrative officer in discharging or removing an officer-or employee in the classified service was “justified” has been settled by a series of decisions. The difference between a review and “a retrial of the case as if it were un-qualifiedly appealed from one court to another” was pointed out in Mayor of Medford v. Judge of First District Court of Eastern Middlesex, 249 Mass. 465, at pages 470-471, and in Selectmen of Wakefield v. Judge of First District Court of Eastern Middlesex, 262 Mass. 477, 482. “Review” indicates “a re-examination of. a proceeding, already concluded, for the purpose of preventing a result which appears not to be based upon the exercise of an unbiased and reasonable judgment. It does not import a reversal of the earlier decision honestly made upon evidence which appears to an unprejudiced mind sufficient to warrant the decision made although of a character respecting the weight of which two impartial minds might well reach different conclusions, and upon which the reviewing magistrate, if trying the whole issue afresh, might make a different finding.” Murray v. Justices of the Municipal Court of the City of Boston, 233 Mass. 186, 189. Mayor of Somerville v. District Court of Somerville, 317 Mass. 106, 109. Board of Public Works of Arlington v. Third District Court of Eastern Middlesex, 319 Mass. 638, and cases cited. ‘ ‘ Justified ” in connection with ‘' review ” means “done upon adequate reasons sufficiently supported by credible evidence, when weighed by an unprejudiced mind, guided by common sense and by correct rules of law.” Selectmen of Wakefield v. Judge of First District Court of Eastern Middlesex, 262 Mass. 477, 482. Costa v. District Court of Eastern Essex, 305 Mass. 85.

The respondent’s return to the Superior Court includes transcripts of the evidence before the police commissioner, the evidence before the civil service commissioners, both of which transcripts were put in evidence before the respondent, and also of the evidence taken before the respondent himself. By virtue of G. L. (Ter. Ed.) c. 249, § 4, as amended by St. 1943, c. 374, § 1, it was “open to the petitioner to contend at the hearing upon the petition [for certiorari] that the evidence which formed the basis of the action com*574plained of or the basis of any specified finding or conclusion was as matter of law insufficient to warrant such action, finding or conclusion.” It was therefore proper for the respondent to include this evidence in his return, whether or not such inclusion would have been proper before the amendment of 1943. Tracht v. County Commissioners of Worcester, 318 Mass. 681, 687. See Common Law Rule 34, 317 Mass. 774. Compare Murphy v. Third District Court of Eastern Middlesex, 316 Mass. 663, 667.

The evidence before the police commissioner tended to show these facts: Some time before April 27, 1946, the officers of -Division 16 had been notified at roll call that an automobile bearing a certain number was “suspected of going around on robberies and larcenies from the person.” About 1:40 o’clock on the morning of that day a report came in from one Ranger that his wallet had been stolen on Arlington Street near Boylston Street. At about 2:20 that morning Officer Dyer of Division 16 saw the suspected automobile stop at a Chinese restaurant on Boylston Street, known as the “Green Pagoda.” Three men got out and went into the restaurant. Ranger’s wallet and another wallet were found by police in the automobile. Thereupon the three men were arrested in the restaurant by officers of Division 16 and Were taken to Station 16 in the patrol wagon. One of the men was one Rollins, who had stolen Ranger’s wallet. One was MacEachern, who owned the automobile. The third man was the petitioner, who was attached to Division 19 but was off duty at the time. When arrested, after a few questions had been asked, the three men were “frisked” and a blackjack not supplied to him by the department was found in the petitioner’s pocket. To carry this was a violation of a rule of the department. When asked what he was doing with it, the petitioner for the first time disclosed that he was a police officer. When the patrol wagon reached the station two additional wallets were found in it near the place where the petitioner had sat. The petitioner said he had known the other two men for about a year. The petitioner’s own story was that he slept until about eleven- o’clock on the night of the twenty-*575sixth and then got up and stayed around the corner of Dudley and Warren streets near his home talking with different people until nearly two o’clock of the twenty-seventh, when MacEachern came along in his automobile and invited the petitioner to go and eat. Rollins came toward them, and all three rode to the “Green Pagoda.” The petitioner testified that he was not intimate with these men but had seen them around the corner for about a year, and that he knew nothing of the wallets and did not know that Rollins had a criminal record.

The evidence before the “disinterested person” designated by the chairman of the civil service commission to hear the matter in accordance with G. L. (Ter. Ed.) c. 31, § 43 (b), as appearing in St. 1945, c. 667, § 1, tended to show the further facts that the MacEachern automobile in which the petitioner rode was driven without lights; that a period of five minutes elapsed while the arresting officers were talking with the three men and were “frisking” them before the blackjack was found on the petitioner and he made known the fact that he was a police officer; that at the police station on the afternoon of the' twenty-seventh the petitioner told the captain in substance that when he was getting into the patrol wagon he heard a thud as if the wallets were thrown into the wagon by someone back of him (presumably MacEachern or Rollins); and that when asked why he had not told that story before his only reply was that he did not want to be a stool pigeon. It appeared that Rollins had a serious criminal record and MacEachern a record of minor offences. The “disinterested person” found the facts substantially in accordance with the evidence outlined above and came to the conclusions that the petitioner’s attitude and failure to cooperate with the other officers at the time of his arrest and while in custody were not conduct becoming an officer and should “not go unnoticed for appropriate disciplinary action,” but that the petitioner was not guilty as specifically charged in the two specifications. The commissioners, however, were not bound by the ultimate conclusions of the “disinterested person.” They could rest their own decision upon his subsidiary *576findings. The commissioners’ action is their own and is not that of the “disinterested person.” G. L. (Ter. Ed.) c. 31, § 43 (b), as appearing in St. 1945, c. 667, § 1.

The respondent at the hearing before him heard some of the witnesses who had previously testified, but nothing new of importance developed. The duty of the respondent was to “review” the entire proceedings from beginning to end to determine “upon all the evidence” whether the discharge of the petitioner was “justified.” G. L. (Ter. Ed.) c. 31, § 45, as appearing in St. 1945, c. 667, § 2.

The petitioner’s requests for rulings can be dealt with according to the subject matters presented without talcing up each separate request.

In order to hold the discharge of the petitioner justified it was not necessary that there be evidence warranting findings that the petitioner knew that his two companions, MacEachern and Rollins, or either of them, was a criminal or that either of them had committed a crime on the night in question. Without saying that such findings would not have been warranted, at the very least it must have been apparent to the petitioner that he was being arrested in circumstances calculated to create a strong suspicion not only of knowledge of what his companions had done but even of guilt on his own part. Conduct becoming a police officer demanded that he should instantly dissociate himself from his companions and clearly align himself on the side of law and order. This he conspicuously failed to do. He waited until the blackjack was actually discovered in his clothing before even mentioning that he was a police officer. At the station, when charged with not having made a full disclosure of all he knew about the wallets, his answer was merely that he did not want to be a stool pigeon. The point need not be labored. The evidence was plainly sufficient to justify his discharge from the police force.

There is nothing in the contention that by granting the petitioner’s third request the judge established “the law of the case” to the effect that the petitioner could not be discharged on the charges preferred unless he knew or should have known that Rollins was a convicted felon and that *577Rollins and MacEachern had been guilty of a felony on the night in question. Freeman v. Robinson, 238 Mass. 449, 451. Slocum v. Natural Products Co. 292 Mass. 455, 458. Rathgeber v. Kelley, 299 Mass. 444, 446. This is not an instance where a case has been tried or has been submitted to a jury under a ruling to which no exception was taken, which governed the subsequent course of the proceedings, and which therefore cannot afterwards be disputed. Santa Maria v. Trotto, 297 Mass. 442, 447. Horton v. North Attleborough, 302 Mass. 137, 141.

No sound objection can be made that the petitioner’s discharge by reason of his conduct, even without knowledge on his part that his companions or either of them was a criminal or had committed a crime on the night in question, was beyond the scope of the specifications. The specifications were perhaps somewhat broadly drawn, but they plainly pointed to the petitioner’s conduct in connection with his arrest on April 27, 1946, as the basis of the charge against him. We think that all of his conduct on that occasion could be- considered in all its bearings. At the hearings the petitioner had the fullest opportunity to present his defence in every aspect. It is plain that as a practical matter additional or more detailed specification could not have helped him, and that he was not prejudiced by lack of it. Proceedings for discharge of persons in the classified service are often conducted by laymen. The requirements of substantial justice must be observed, but the technical accuracy of indictment and trial in a criminal court cannot be expected. McCarthy v. Emerson, 202 Mass. 352, 354. Swan v. Justices of the Superior Court, 222 Mass. 542. Graves v. School Committee of Wellesley, 299 Mass. 80, 86. Lowry v. Commissioner of Agriculture, 302 Mass. 111, 117. Higgins v. License Commissioners of Quincy, 308 Mass. 142, 145-146. Moran v. School Committee of Littleton, 317 Mass. 591, 596. Moreover, it does not appear that before the respondent or at any other time in the course of the proceedings the petitioner made any objection to the specifications or any contention that the hearings or the decisions made extended beyond the specifications. Mayor of Medford v. Judge of *578First District Court of Eastern Middlesex, 249 Mass. 465, 471-472. Substantial justice was done so far as respects the form of the accusation. Whitney v. Judge of the District Court of Northern Berkshire, 271 Mass. 448, 458-463.

Certain inaccuracies in the subsidiary findings of the police commissioner have become unimportant in view of the full hearing subsequently held before the disinterested person appointed by the chairman of the civil service commission, his ample findings of subsidiary facts, and the independent decision of the commission.

We have dealt with all points presented and argued.

Exceptions overruled.