The defendants were convicted of armed robbery and armed assault with intent to murder on the basis of identifications made by Paul K. Foley, a witness who had been hypnotized before he made a positive identification of either defendant. We reverse the convictions because Foley’s identification testimony was not admissible in evidence.
We recite the basic circumstances of the crime and of the events leading to the defendant’s arrests. On the night of February 14,1980, Foley was working at his part-time job as a clerk *637at a beer and wine store in Brockton. About 9:30 p.m. , two men entered the store, one of whom was carrying a gun. The man carrying the gun was older than the other man. They took money from the cash register and from a paper bag. The older man shot Foley in the head twice. Foley was able to obtain assistance, however, and was taken to a hospital. He gave descriptions of each man to the police, but was unable to develop composite drawings with which he was satisfied.
On March 10, 1980, at the suggestion of his brother-in-law, a sergeant in the Boston police department, Foley was hypnotized. The police detective conducting the hypnotic session told Foley beforehand that he would get a clearer picture in his mind of what happened on February 14. In the course of the hypnotic session, the detective said Foley should picture himself watching television at home and visualize what happened. After the hypnosis, Foley attempted composite drawings again. He was content with the new composite of the younger man.
On March 27, 1980, seventeen days after the hypnotic session, Foley was at home watching the eleven o’clock news on television when he saw what he believed was the older man who had shot him. He called the Brockton police and later that night identified a picture of the older man in a book containing pictures of white males and said that a picture of another man looked like the younger man who also robbed the store, but that he looked younger in the picture. On March 28, 1980, Foley saw what he believed was the younger man on the noontime news. Foley again called the police. The defendants were arrested and indicted.
The facts just recited are taken largely from the transcript of the hearing on the defendants’ motions to suppress Foley’s identification testimony. Foley testified at that hearing that he had a “[v]ery vivid memory” of what the robbers looked like and that he “will never forget them.”2 The full pattern of descriptions Foley had given to the police need not be repeated *638here. There was uncertainty in the descriptions on several points. Foley testified that the younger man had a mustache and wore glasses. The Brockton detective assigned to this case testified that, shortly after the incident, Foley had said he was not sure whether the younger man had a mustache and that it was possible that he was wearing glasses but he was not sure. Foley’s statements concerning the complexion of the older man, mentioning pock marks at some times and not at others, were not consistent. There was no expert testimony as to whether it was merely coincidence or the product of suggestion that, after the “television viewing” technique was used during hypnosis, Foley discovered the defendants on television.3
When he denied the defendants’ motions to suppress, the motion judge did not have the guidance of our opinion in Commonwealth v. Kater, 388 Mass. 519 (1983), concerning the admissibility of testimony of witnesses who have been hypnotized. He did have our opinion in Commonwealth v. A Juvenile, 381 Mass. 727 (1980), which indicated only that the use of hypnotically aided testimony presented problems that needed special attention but did not lay down any firm guidelines. We need not consider the circumstances under which the hypnotic session was conducted because, even if it had been conducted according to adequate procedural safeguards (see Commonwealth v. Kater, supra at 529-530; Commonwealth v. A Juvenile, supra at 732-733 n.8), Foley’s identification testimony was inadmissible.
There is nothing in this record from which to conclude that Foley’s posthypnotic testimony was uninfluenced by hypnosis or that his testimony was based solely on his prehypnotic memory. In the absence of such a showing by the Commonwealth (see Commonwealth v. Kater, supra at 527; Commonwealth v. A Juvenile, supra at 734), a witness’s posthypnotic memory of prehypnotic events, not recalled before hypnosis, is inadmissible (Commonwealth v. Brouillet, 389 Mass. 605, 607-608 [1983]), except in limited circumstances not involved *639here (Commonwealth v. Kater, supra at 528-529). The admission of Foley’s identification testimony, the only evidence placing the defendants at the scene of the crime, was prejudicial error. See id. at 530. Contrast Commonwealth v. Watson, 388 Mass. 536, 542 (1983) (defendant not prejudiced by admission of posthypnotic identification); Commonwealth v. Stetson, 384 Mass. 545, 552-554 (1981) (same).
The judgments are reversed and the verdicts are set aside. The cases are remanded to the Superior Court for further proceedings.4
So ordered.