The defendant was convicted in the Superior Court of first degree murder in a case taken under G. L. c. 278, §§ 33A-33G. The case is here on assignments of error.
*172 The facts are not in dispute. At approximately 7:30 a.m. on December 19, 1971, the defendant, incarcerated at the Massachusetts Correctional Institution at Walpole, entered the inmate cafeteria where, with his own tray empty, he sat at a table of Black Muslims, including one Irving 2X Jones who was their minister and leader. Another inmate, Frank Smith, entered the dining room shortly afterward, and the defendant thereupon left the cafeteria, remaining in the hall outside where he paced back and forth. Several minutes later Smith departed the dining area and encountered the defendant in the hallway. A number of guards were in the immediate vicinity of the confrontation and they all testified that the defendant twice stabbed Smith in the chest with a sharpened kitchen knife, shouting “Allah!” as he did so. Smith fell to the ground and was pronounced dead at 9:05 a.m. the same day.
The defense relied on a theory of insanity at the trial. One doctor had examined the defendant for the Commonwealth. He was of the opinion that the defendant was criminally responsible at the time of the incident. Two psychiatrists testified for the defendant and described his conversion to the Muslim religion and his burgeoning obsession with the idea that Smith was a threat to that religion in general and to Jones, whom he had earlier threatened, in particular. Their conclusion was that he was not criminally responsible for his assault on Smith.
We discuss the assignments of error seriatim, making such reference as may be necessary to additional testimony.
1. The defendant first alleges error in the denial by the trial judge of a pre-trial motion to inspect grand jury minutes. He argues that such inspection was necessary because he was being held in the prison segregation unit, and neither he nor his counsel had ready access to inmates and to prison guards who might be potential witnesses. The denial of this motion was not error. He was
*173
not entitled to inspection of grand jury minutes under the law in effect at the time of the trial in the absence of a showing of a “particularized need.”
Commonwealth
v.
Carita,
As we view the record, the defendant was provided wifh broad discovery, including the reports of prison guards, a list of the names of witnesses, and copies of
*174
statements of witnesses to be relied on by the Commonwealth, as well as a list of names and addresses of witnesses who appeared before the grand jury. In fact, the Commonwealth’s answer indicates there was just one such grand jury witness and he did not testify at trial. It is questionable that even the liberalized
Stewart
rules would require inspection in these circumstances. We are not impressed by the defendant’s suggestion of need based on possible evidence of conspiracy which was never introduced at trial.
Dennis
v.
United States,
2. The defendant complains of the denial of his motion to prohibit the Commonwealth from employing a prior conviction for rape to impeach his credibility were he to testify, stating that this could serve only to prejudice him because the conviction has no bearing on such credibility. It is clear that under G. L. c. 233, § 21, witnesses may be impeached by proof of prior conviction. This statute applies to a criminal defendant testifying in his own behalf.
Commonwealth
v.
Subilosky,
3. The defendant claims that he was placed in jeopardy twice for the same offense and by the same sovereign in being administratively punished in prison before trial. This claim is based on his confinement in a segregated unit at the Massachusetts Correctional Institution at Walpole immediately following the incident of December, 1971. He claims that this confinement constituted administrative punishment, and that consequently his trial on the murder indictment was a violation of the provision of the Fifth Amendment to the United States Constitution applicable to the States through the Fourteenth Amendment.
Benton
v.
Maryland,
A review of the voir dire testimony on this point leads us to conclude that there was ample support for the judge’s findings. The deputy superintendent of the prison, arriving there shortly after the stabbing, observed a group of approximately fifty non-Muslim blacks congregated outside the cell block where the Muslims were living. He concluded that the Muslims should be segregated because of the existing turmoil. The defendant strongly argues that by the end of the summer of 1972 all the Muslims save himself were transferred back to the general population, keeping him confined, he says,
*176
for punishment rather than protection. The deputy superintendent testified, however, that the defendant was in danger of his life at that time and, in his opinion, would not have been safe in the general population. The judge could have concluded that a special need for protection existed. See
Smith
v.
Swenson,
We conclude that the defendant was not punished administratively and that his trial for murder did not place him in double jeopardy. Further, we note in passing that even if his segregated confinement for almost fifteen months could be characterized as a form of punishment we know of no decisions in which the combination of administrative punishment of an inmate and his criminal conviction has been held to result in double jeopardy. In fact there are many decisions to the contrary. See, e.g.,
United States
v.
Apker,
4. The defendant argues that his right to have a speedy trial under both Federal and State law was violated. He relies on G. L. c. 277, § 72A, as well as on the Federal and State constitutional guaranties.
General Laws c. 277, § 72A, as appearing in St. 1965, c. 343, establishes a priority for a trial of defendants already in custody.
Commonwealth
v.
Lauria,
The chronology of this case is of interest. An indictment on January 7, 1972, was followed by the defendant’s motion for a speedy trial on February 11, 1972. At no time was an application pursuant to § 72A filed. But in the absence of an indication that the defendant was given notice of his right to apply, as required by the statute, we treat the motion for a speedy trial as satisfying the application requirement. Cf.
Commonwealth
v.
Gove,
It is evident from this timetable that although defense counsel never formally requested a continuance, “a substantial part of the delay . . . was obviously caused by him and, in addition, was for his benefit.”
Commonwealth
v.
Loftis,
The defendant also argues the denial of his constitutional right to a speedy trial under the Fourteenth Amendment to the Constitution of the United States (see
Klopfer
v.
North Carolina,
The delay in this case from indictment to trial was slightly less than fourteen months. In
Commonwealth
v.
Gove,
In light of that fact, and while we do not applaud a delay of fourteen months in trial, we cannot accept the defendant’s argument on this point. We discover no prejudice in the delay. The only prejudice alleged is based on the defendant’s segregation of almost fifteen months in block No. 10 while awaiting trial, which we have already concluded was for the defendant’s protection and, hence, was not the result of any trial delay. Any other deprivations remain “speculative and insubstantial.”
Commonwealth
v.
Gove,
5. The defendant lodges three objections to the expert testimony of Dr. James Christy, who testified for the Commonwealth on the question of the defendant’s sanity at the time the offense was committed.
The first objection is that the doctor had insufficient grounds on which to render his opinion. He had testified to having examined the defendant and was then asked by the prosecution whether he had formed an opinion. He answered over the defendant’s objection, and it is now argued that since he was not asked whether his opinion was based on reasonable medical certainty the jury may have considered expert opinion which rested on nothing more than conjecture.
Nass
v.
Duxbury,
The defendant also tells us that Dr. Christy’s qualifications were inadequate. It appeared that he had never taken the board examination in the psychiatric specialty since he lacked certain requirements of residency and training. It did appear, however, that he had been doing psychiatric work at the Bridgewater State Hospital for five years, serving as principal psychiatrist and then as assistant medical director and, finally, as acting director.
*182
We have repeatedly stated that the question of an expert’s qualifications is for the trial judge, and his determination will be reversed only on an abuse of discretion or error as matter of law.
Commonwealth
v.
Spencer,
There is complaint that the judge failed to make a preliminary finding that Dr. Christy was qualified to testify as an expert on sanity. He argues that this failure means that the determination was left to the jury, which is reversible error.
Winthrop Prods. Corp.
v.
Elroth Co. Inc.
6. It was not error to deny the defendant’s motion for a directed verdict of acquittal. He argues that the evidence was overwhelming that his acts were motivated by other than a rational mind. But there was sufficient
*184
evidence for the jury, who were charged in accordance with the test set forth in
Commonwealth
v.
McHoul,
The requisite malice could also have been found from the defendant’s intentional use of a deadly weapon, which gives rise to an inference of malice unless by the circumstances it is disproved.
Commonwealth
v.
Young,
7. During his cross-examination of one of the defendant’s psychiatrists, the prosecutor asked the following question in reference to the Muslim religion: “Religious values of secondary importance, main concept is group solidarity — anti-white. A pro-Black feeling primarily?” The defendant objected to the question, and assigns its allowance as error, stating that it was irrelevant and highly inflammatory in its effect on an all white jury. Evidence is not admissible if its purpose is to prejudice the jury, but the burden is on the excepting party to show that this is so.
Godfrey
v.
Old Colony St. Ry.
8. The defendant raised a number of objections to the judge’s instructions to the jury which separately and in toto are said to have resulted in prejudicial error. First, the defendant states his grievance that on two occasions the judge said to the jury that the defendant had killed the deceased, statements which invaded the jury’s province to find the facts, and precluded the possibility
*186
of a not guilty verdict. But these statements seem to have been made only in the course of the judge’s charge on the insanity defense.
3
Read in that context, it appears that the judge was merely explaining what verdict to return in case certain facts were found. See
People
v.
Mattel,
The defendant holds that the judge effectively discredited the story he told the psychiatrists by implying that he might have put on “rose-colored glasses” in telling them of the incident. Our examination of the transcript indicates that this comment appears in the context of a general discussion of the credibility of witnesses wherein the judge indicates the possibility that in a given case an interested party might stretch a point. However the judge added, “I don’t say that is the fact in this case, but you think of it, yes, you do.” The judge paralleled his comments with a similar reference to the interest of the correctional officers in the outcome, mentioning the possibility that they too may have put on their “rose-colored glasses.” There was no error. The judge was acting within his province.
Cahalane
v.
Poust,
In charging the jury on the presumption of innocence the judge instructed: “The presumption of innocence is not evidence, not evidence which you retain for the dura *188 tian of the case up to and including your deliberation; the presumption of innocence is a presumption which, upon the introduction of evidence on the question of the guilt or innocence of this defendant, the presumption disappears and then you decide the case on the evidence.” After objection by the defendant, the judge further instructed: “A presumption of innocence is not evidence for the jury in favor of a defendant. A presumption is not evidence but is a rule which governs until sufficient evidence to the contrary appears. . . . When sufficient evidence to the contrary appears, then you decide the case on the evidence, and the presumption is not considered thereafter.” The defendant assigns this as error, contending that the judge must instruct that the presumption of innocence stays with the defendant until the jury are convinced of the defendant’s guilt beyond a reasonable doubt.
The presumption of innocence has been aptly described as “a source of mysticism and confusion.” McCormick, Evidence, § 309, p. 647 (1954). The presumption serves as a focus on the prosecutor’s burden of producing evidence of guilt and persuading the jury of the guilt beyond a reasonable doubt. See
Carr
v.
State,
The defendant objected to the judge’s instruction on manslaughter as blurring the distinction between guilty of voluntary manslaughter and not guilty by reason of insanity. The judge charged: “Ordinarily if a person becomes suddenly aroused by passion and, as the saying goes, loses his head or there is some provocation and a person retaliates to a show of force, or whatever is teasing the person, and he has the misfortune of killing someone, that is known as voluntary manslaughter and it is excused because of the weakness of human nature.” Further on he told the jury that they must be satisfied *190 that as a result of provocation the defendant was “unable to control his action.” The defendant suggests that if the defendant had “lost his head” or was “unable to control his actions,” his conduct came within the test for lack of criminal responsibility, not voluntary manslaughter.
We do not believe that this instruction deviated substantially from the definition of manslaughter as “a killing from a sudden transport of passion or heat of blood, upon a reasonable provocation and without malice, or upon sudden combat.”
Commonwealth
v.
Soaris,
We do not see error in the judge’s statement to the jury that the deceased represented no current threat to the defendant at the time of the incident, for the judge may properly rule on whether the evidence is sufficient to demonstrate particular circumstances warranting the verdict of manslaughter.
Commonwealth
v.
Campbell,
We conclude that the judge’s instructions considered separately and together did not establish error.
9. Consonant with our duty under G. L. c. 278, § 33E, we have reviewed the record and transcript and find no grounds to order a new trial or direct a verdict of a lesser degree of guilt.
Judgment affirmed.
Notes
Since we conclude that the case is governed by the principles set forth in
Commonwealth
v.
Loftis,
While the statute puts no explicit limits on the judge’s discretion to order an extension of the statutory period, we do not believe that the Legislature intended that the discretion be unbridled; some element of reasonable justification should be present. See 1959 House Doc. No. 473; 1960 House Doc. Nos. 578, 584 and 3036; 1961 House Doc. Nos. 228 and 2157; 1961 Senate Doc. No. 563; 1963 House Doc. Nos. 1232 and 3406; 1963 Senate Doc. No. 813. For possible guidance as to what might justify delay, see A. B. A. Standards Relating to the Administration of Criminal Justice, Speedy Trial, § 2.3 (1974), and commentary in Approved Draft (1968).
The judge stated:
“And you see what the distinction is. Not guilty by reason of insanity means that the act occurred. Okay. The defendant did stab Smith and Smith did die so that the act occurred, but at the time of the act you the jury determine in accordance with this test that the defendant was not responsible. In that respect you would be required to return a verdict of not guilty by reason of insanity. . . .
“You might say, ‘Well, what about this business of the defendant not being proven beyond a reasonable doubt in your judgment to be criminally responsible? What does that mean that the jury has to do?’ Well, you have in mind that the defendant has killed somebody and the question is whether or not he did it with or without legal justification.”
