
353 Mass. 426 (1967)
233 N.E.2d 205
COMMONWEALTH
vs.
ALVIN MITCHELL.
Supreme Judicial Court of Massachusetts, Hampden.
December 4, 1967.
December 29, 1967.
Present: WILKINS, C.J., SPALDING, WHITTEMORE, SPIEGEL, & REARDON, JJ.
Stephen W. Silverman for the defendant.
Matthew J. Ryan, Jr., District Attorney (Leonard E. Gibbons, Assistant District Attorney, with him), for the Commonwealth.
SPALDING, J.
Under an indictment charging unlawful sale of a narcotic drug (heroin), the defendant was found guilty by a jury. The case, having been tried subject to G.L.c. 278, §§ 33A-33G, comes here by appeal.
We summarize the evidence as follows: Springfield police officers, to whom the defendant was known as a user and supplier of narcotics, had kept him under surveillance for about a month prior to December 15, 1966. On December 15 Officers Coville and Collins saw the defendant, who was sitting in a diner on Main Street, come to the door of the diner and call to one Thomas E. Harris, who was passing by. Harris stopped and he and the defendant had a conversation. They then walked to the vestibule of the Paramount Hotel where the defendant was seen to "hand ... something" to Harris and Harris in turn gave the defendant some paper currency. Following this exchange both men entered the hotel. A short time later Harris left the hotel alone and was followed by the officers into the Lyman Hotel where he was arrested in the corridor outside his room. A search of Harris revealed a hypodermic needle and an eyedropper.
Harris admitted to the officers that he had just purchased heroin from the defendant in exchange for $10 and that he had used the drug after entering the hotel with the defendant. Harris told the officers that since he had no hypodermic needle or eyedropper he borrowed them from the defendant.
*428 As a result of their conversation with Harris, the officers set out to find the defendant. They observed him walking on Main Street and placed him under arrest. The defendant resisted the officers and as they were attempting to put him in the police car he pulled something out of his pocket and started to stuff it in his mouth. The officers prevented this and took from the defendant's hand a packet which contained heroin.
The sole question for decision arises out of the defendant's motion to suppress. The defendant sought to suppress any evidence seized during the arrest of either Harris or himself. The motion was denied subject to the defendant's exception.
In support of this exception the defendant argues that on the basis of what the police officers observed when the exchange between the defendant and Harris took place probable cause was lacking to arrest either. He further argues that information gained from the arrest of Harris cannot validate the arrest of the defendant because this was the fruit of an illegal search.
As was said in Beck v. Ohio, 379 U.S. 89, 91, "The constitutional validity of the search in this case ... must depend upon the constitutional validity of the ... arrest. Whether the arrest was constitutionally valid depends in turn upon whether, at the moment the arrest was made, the officers had probable cause to make it  whether at that moment the facts and circumstances within their knowledge and of which they had ... trustworthy information were sufficient to warrant a prudent man in believing that the ... [defendant] had committed or was committing an offense." Applying those principles here, we are of opinion that the officers had probable cause to arrest Harris and the defendant and that the evidence resulting from the arrests was properly admitted. The defendant had been under police surveillance for approximately one month. He was known to the police to be an illegal user and supplier of drugs. When the police observed him exchanging a small packet for money under surreptitious circumstances, *429 their belief that felonies (in which both Harris and the defendant were participating as possessor and seller respectively) were being committed in their presence was amply justified. Ker v. California, 374 U.S. 23. See Brinegar v. United States, 338 U.S. 160, 172-176; Draper v. United States, 358 U.S. 307, 310-314; Henry v. United States, 361 U.S. 98, 102; Commonwealth v. Holmes, 344 Mass. 524, 525; Commonwealth v. Lawton, 348 Mass. 129, 133. Compare Commonwealth v. Rossetti, 349 Mass. 626, 633-634.
Judgment affirmed.
