
410 Mass. 75 (1991)
571 N.E.2d 7
COMMONWEALTH
vs.
VINCENT CRAWFORD (and three companion cases[1]).
Supreme Judicial Court of Massachusetts, Suffolk.
January 10, 1991.
May 9, 1991.
Present: LIACOS, C.J., WILKINS, NOLAN, O'CONNOR, & GREANEY, JJ.
Carmel Motherway, Assistant District Attorney, for the Commonwealth.
William F. Fahey (Francis J. Hurley with him) for Gail Pina.
Thomas J. Amoroso for Vincent Crawford.
NOLAN, J.
This matter involves an interlocutory appeal by the Commonwealth from the Superior Court's order of suppression of evidence. Police seized the evidence in a warrantless search at the scene of an arrest. The judge determined that the arresting officer did not have probable cause to believe *76 either that a crime was being committed or that contraband would be found in the automobile which was searched. We reverse the order and remand for a new hearing on the issue of the reliability of the information provided by an unidentified informant.
1. Facts. The motion judge found the following facts: On the evening of October 21, 1987, State Trooper Stephen Matthews met with a confidential informant concerning the activities of the defendant Vincent Crawford. The informant had learned from Crawford that Crawford was planning to replenish his supply of cocaine that evening. The informant also told Officer Matthews that Crawford would have with him cocaine which would be readily available for sale. According to the informant, Crawford had sent his girl friend to New York that day to pick up a large amount of cocaine. Crawford told the informant that the woman would return to Boston by rail, arriving sometime around midnight. The informant said Crawford was planning to meet the woman at South Station, Boston, and would be driving his grey Datsun Maxima automobile, Massachusetts registration 217MPC.
As a result of this information, Officer Matthews confirmed with the Registry of Motor Vehicles that Crawford owned a grey Datsun Maxima, Massachusetts registration 217MPC. Officer Matthews also discovered that Crawford's driver's license had been suspended.
At about 11:30 P.M. on October 21, 1987, Officer Matthews and four other officers established a stakeout at the South Station Amtrak terminal in Boston. Shortly after midnight, the officers noticed Crawford. Crawford was not driving the Maxima described in the tip, but he was driving a Datsun Sentra automobile, which he parked near South Station. The Maxima, driven by another man, followed the Sentra. Crawford then conversed with the driver of the Maxima.
Shortly after 1:00 A.M., the Amtrak train from New York arrived at the station. Officer Matthews had learned that the train was scheduled to arrive at midnight but had been delayed. Crawford got into the Sentra and the driver of the Maxima approached two women who had come from the *77 train. One of these women was the defendant Gail Pina. The three walked toward Crawford and the vehicles. Officer Matthews observed Pina carrying a handbag and a pink travel bag. Pina and the other women started to get into the Sentra, the car occupied by Crawford.
At this point, Officer Matthews and the other officers intervened. All of the individuals were frisked for weapons, and Officer Matthews seized the pink travel bag from Pina. In the bag was a large blue object which Officer Matthews knew from his experience to be consistent with a packaged kilogram of cocaine.
Officer Matthews told all four individuals that they were under arrest for trafficking in cocaine and advised each of them of their rights. Pina then told Officer Matthews that the other woman had nothing to do with the cocaine. Officer Matthews opened the pink bag and discovered two wrapped kilograms of cocaine inside. Officer Matthews then searched the Sentra. On the floor behind the seat, he discovered a shoe box containing a large amount of cocaine. A search of Crawford revealed cocaine in his socks.
Crawford and Pina moved to suppress the evidence on the grounds that there was no probable cause sufficient to support either the arrest or the search of the car. The trial judge held an evidentiary hearing to determine whether there was probable cause.
Officer Matthews relied heavily on the information provided by the confidential informant in determining that there was probable cause. During the inquiry into the credibility of the informant, Officer Matthews stated that information from this informant had, in the past, led to the arrest of persons and the seizure of controlled substances. The officer refused to reveal the names of those individuals arrested out of fear that doing so would effectively identify the informant and subject the informant to grave danger. On the Commonwealth's suggestion, the judge held an in-camera hearing, at which only the judge, the officer and the court reporter were present, and during which the judge inquired into the credibility of the informant. He emerged from the hearing and *78 announced that the information provided therein, combined with the open court testimony, had satisfied both the basis of knowledge test and the veracity test.
The judge later reconsidered his actions. He held that the in-camera hearing violated the defendant's confrontation rights and was thus illegal. Disregarding the in-camera testimony, the judge held that there was not sufficient corroboration of the details of the tip to allow it to give rise to probable cause. He therefore excluded the evidence. The Commonwealth applied for leave to file an interlocutory appeal. A single justice of this court allowed the application. We vacate the order of suppression and remand for an additional hearing.
2. Probable cause. Probable cause to arrest exists when the facts and circumstances in the arresting officer's knowledge, and of which he has reasonably trustworthy information, are sufficient to warrant a person of reasonable caution to believe that an offense was or is about to be committed. Commonwealth v. Gullick, 386 Mass. 278, 283 (1982). The tip, if it could properly be relied upon, supplied the officer with reason to believe that a crime (trafficking in cocaine) was being committed at South Station. See Draper v. United States, 358 U.S. 307 (1959). In the absence of the tip, there was no such probable cause. The crux of the case, therefore, is whether the officer could properly rely upon the information provided by the informant.
In order to be deemed reasonably trustworthy, information provided by a confidential informant must satisfy the two-pronged test first set forth in Aguilar v. Texas, 378 U.S. 108 (1964), and Spinelli v. United States, 393 U.S. 410 (1969), and adopted by this court in Commonwealth v. Upton, 394 Mass. 363 (1985). The Commonwealth must (1) demonstrate the basis of the informant's information and (2) put forward sufficient indicia of veracity to justify probable cause.
There was testimony in open court which, if believed, would satisfy both prongs of the Upton test. The basis of the informant's knowledge was revealed when the officer testified *79 in open court that the defendant Crawford had told the informant of the plan.
There was also sufficient testimony in open court to satisfy the veracity test. The veracity test may be satisfied by demonstrating the credibility of the informant. That credibility, in turn, may be established by showing that information provided in the past by this informant has proved to be accurate. See Commonwealth v. Valdez, 402 Mass. 65, 70-71 (1988). In this case, the officer testified that the informant had, in the past year, given information which led to the arrest and indictment of two unnamed persons and the seizure of over a kilogram of cocaine. In Commonwealth v. Perez-Baez, ante 43 (1991), we held that a prior tip regarding the possession of cocaine which leads to an arrest and a seizure of cocaine is sufficient to satisfy the veracity aspect of the test.
However, it is apparent from the record that the judge was not entirely convinced that the officer was being candid in his testimony in open court. The officer refused to reveal the names of the two individuals arrested pursuant to the informant's prior tip. The prosecutor suggested that the officer tell the judge the names of the individuals in-camera, so as not to compromise the informant. The officer did so and the judge was then apparently convinced that the officer was telling the truth. Later, the judge decided that the in-camera hearing was inappropriate and returned to his prehearing conclusion, that he was unconvinced by the trooper's statements concerning the informant's reliability.
The judge was correct in determining that the in-camera interview with the police officer, attended by neither the prosecutor nor defense counsel, was inappropriate. The Commonwealth bore the burden of proving to the judge that the evidence was seized in a lawful manner, and defense counsel should have been present at every stage of the prosecution's case.[2] The judge should not have conducted this hearing in *80 the absence of defense counsel.[3] The judge, therefore, properly did not rely upon the testimony obtained therein.
However, in the circumstances of this case, the judge should not have proceeded directly from a determination that the in-camera proceeding was improper to exclusion of the evidence. The stated goal of the exclusionary rule is to encourage police officers to conform their conduct to the dictates of the Constitution. Commonwealth v. Amral, 407 Mass. 511, 516 (1990). Franks v. Delaware, 438 U.S. 154, 165-166 (1978). The judge should have given the Commonwealth every opportunity to prove the existence of probable cause in a manner consistent with the defendant's rights and also without unnecessarily requiring the disclosure of the informant's identity.
The proper course of action in these circumstances is for the judge to conduct another recorded in-camera hearing, this time inviting the defense counsel and the prosecutor to attend. If, in the presence of the defendant's attorney, the officer reveals the information required to satisfy the judge, the evidence should not be suppressed. If the officer refuses so to testify, the judge may then suppress the evidence. This matter is to be remanded for a new hearing on this point.
3. Search of the automobile. The validity of the search of the automobile is dependent on the outcome of the new hearing. If the officer was not entitled to rely on the informant, the search was illegal.
*81 Because we hold that a new hearing must be held, we remand this case to the Superior Court for further proceedings consistent with this opinion.
So ordered.
NOTES
[1]  The three companion cases are one against Vincent Crawford and two against Gail Pina.
[2]  This case differs from Commonwealth v. Amral, 407 Mass. 511 (1990), in which we prohibited defense attorneys from attending an in-camera hearing held to determine whether there was a sufficient preliminary showing of misstatement in the warrant affidavit to justify a hearing under Franks v. Delaware, 438 U.S. 154 (1978). Here, the Commonwealth has yet to satisfy its burden of convincing the judge that the warrantless search was supported by probable cause. In Amral, a case involving a search conducted pursuant to a warrant, the Commonwealth had already met its initial burden and the defendant was attempting to impugn the sworn statements in the affidavit. Because the defendant was not entitled to a hearing on the alleged misstatements without first making a substantial preliminary showing, the defendant had no right to have his attorney present at the in-camera hearing designed to determine whether that preliminary showing had been made.
[3]  In making this determination, we rely neither upon the Sixth Amendment to the United States Constitution nor article 12 of the Massachusetts Declaration of Rights but rather on our general powers of supervision over lower courts.
