delivered the opinion of the Court.
Plaintiff in error was the defendant in the trial court and will be so referred to herein. By an information *464filed May 2, 1958, it was charged that on April 25, 1958, defendant killed and murdered Regina Knight. He entered pleas of not guilty and of not guilty by reason of insanity at the time of the alleged commission of the offense. The trial court ordered the trial of the issues thus formed to be consolidated and the case was tried commencing November 17, 1958. The jury found the defendant guilty of murder in the first degree and fixed the punishment at death. Thereupon, writ or error was issued.
There is no dispute as to the actual facts of the homicide. In fact, counsel for defendant conceded at the trial that if the evidence established beyond a reasonable doubt the sanity of the defendant the facts established his guilt of murder. (Counsel contended, however, that the jury should have been allowed to consider murder in the second degree.)
Defendant was released from a federal penitentiary on April 22, 19581 He immediately came to Denver and went to the office of Merrill Knight, a Denver attorney who had befriended him in the past. He made efforts to contact Knight in the latter’s office and on the night of April 24, 1958, made plans to burglarize the Knight home and to rob members of the family. With this in mind he tried but was unsuccessful in his efforts to obtain a gun. Defendant said that he was convinced that he would again become involved in trouble and that this was his motivation for the robbery. He then intended to go to Texas or Mexico. He decided to rob the Knights merely because they were well off and accessible. The fact that Knight had befriended him was not significant in defendant’s thinking.
- On Saturday, April 25, he took a taxicab to the Knight home located in Arapahoe County on the outskirts of Denver. Finding no one at home, he entered the house through the back door, searched it and found a 32 caliber pistol with four shells and also a rifle which he loaded. He then gathered up what money he could find and *465waited for the Knights to return. As individual members of the family arrived home, he bound and gagged them and waited for the others. By evening both Mr. and Mrs. Knight, their son, Kenneth, and a daughter, Karen, had been tied up and imprisoned in different rooms of the house. According to defendant’s statement, his plan was to rob them and leave them bound and gagged so as to provide him time for a get-away. Although Mr. Knight was bound hand and foot, he managed to stand up and hobble around the room and refused to obey defendant when he was told to lie down. Defendant shot him three times and then went to the master bedroom and shot Mrs. Knight through the head. The pistol was then empty. Defendant then obtained the rifle, went upstairs and shot and killed Karen. Kenneth had meanwhile managed to free his feet and ran out the front door as the defendant came back downstairs apparently for the purpose of shooting and killing him. One shot was fired at Kenneth as he ran across the front yard. The rifle then jammed, permitting Kenneth to escape. Defendant collected his clothes and tried to get away in one of the Knight cars, but was captured by some of the neighbors who had been alerted by Kenneth. Although defendant harbored some resentment toward Knight, this does not appear as the motive for the killings. The murders were perpetrated coldly and dispassionately because defendant believed it necessary to the success of the robbery and in order to effect his escape.
On the issue of his insanity, the defendant called several witnesses. There were two psychologists; a psychiatrist who had examined the defendant while he had been confined in the Colorado State Hospital in 1955; another psychiatrist testified concerning the defendant’s mental condition while he was confined in Leavenworth Penitentiary during the early part of 1958. Two other psychiatrists had examined defendant during the period following the homicide and prior to trial. The testimony of all of these witnesses was more or less consistent in *466classifying the defendant as a schizophrenic personality with paranoid trends. The doctors conceded the ability of the defendant to recognize right from wrong, but testified that he was unable to refrain from doing wrong.
The People presented five psychiatrists, all of whom testified that the defendant was legally sane. Their testimony was to the effect that the defendant was a “sociopath” or “constitutional psychopath.” All of the expert testimony detailed the past life of the defendant and included a full account of the examination which was given him. From this it would appear that although the defendant was highly intelligent, he had also shown a high degree of irresponsibility which had involved him in continuous trouble from the time he was a small boy.
These prosecution physicians were unable to find any system of delusions or other evidence indicating schizophrenia. They conceded the irresponsibility of the accused and said that he was “put together wrong” but that he was not “legally insane” in that he had the capacity to recognize right and wrong and to refrain from choosing the wrong course of action.
This question of sanity was one of fact, and since the jury found this fact in accordance with the opinions of eminent expert psychiatrists who from the record presented were entirely justified in their opinions, we are not at liberty to reach a conclusion different from that of the trier of the facts.
It is noteworthy that the trial court was scrupulous in its efforts to insure that the accused had adequate psychiatric testimony. Expert witnesses were brought in from outside the state and the court was careful to appoint other psychiatrists at the defendant’s request.
Two of the People’s witnesses, Drs. Hilton and Rymer, were called in by the District Attorney immediately after the commission of the crime. The major issue on this review pertains to their examination and testimony. They interviewed the defendant on April 25, 1958, in the Arapahoe County jail prior to his arraignment and *467before counsel had been appointed to defend him. He had spoken freely to these physicians and from this interview they concluded that he was legally sane. Although they had identified themselves as doctors, they had not revealed that they were psychiatrists and that they were giving the defendant a psychiatriatic examination. However, at the end of the interview this fact was brought to the attention of the accused and he then stated that he had supposed that they were psychiatrists. It is also inferrible from the testimony of various witnesses that the accused was aware that Drs. Hilton and Rymer were psychiatrists because he was not lacking in such experience. He had had numerous such examinations previously and on a prior occasion had been subjected to the Rorschach psychological test.
A total of 19 errors have been assigned by the defendant. We deem it necessary to consider only those which have been argued. The points raised may be summarized as follows:
1. That it was error for the trial court to receive the testimony of Drs. Hilton and Rymer on rebuttal. This is predicated on the contention that C.R.S. ’53, 39-8-1 is said to provide a mandatory and exclusive procedure for raising and trying the issue of insanity in a criminal case. Examination of the accused during confinement and before arraignment violated the statute and is contrary to the due process and equal protection guarantees of the Colorado and United States constitutions.
2. That the trial court erred in allowing Drs. Rymer and Hilton to testify concerning results of the examination which was had immediately after the arrest of the defendant. It is contended that this constituted compulsory self-incrimination in violation of the Colorado constitution.
3. That the court erred in submitting the case to the jury on the basis of C.R.S. ’53, 40-2-3. It is claimed that this section, which classifies murder committed in the perpetration of arson, rape, robbery, mayhem or bur*468glary, as first degree murder, is unconstitutional in that it deprives the accused of his right to a jury trial with respect to the essential element of malice, and is thus in violation of the Fourteenth Amendment, Constitution of the United States and Article II, Section 23, Constitution of Colorado.
4. That defendant was deprived of a fair and impartial trial in that the jury reached a verdict following deliberations which required only 25 minutes. It is said that the jury thus failed and refused to read and consider the instructions of the court and that it followed its preconceived notions concerning the guilt of the defendant.
I.
The question whether the statutory procedure is so exclusive that it prevents other examinations.
C.R.S. ’53, 39-8-1 provides:
“Plea of insanity.— (1) If one of the defenses of the defendant is insanity, it must be pleaded at the same time with all other pleas, unless it is to be the sole plea of the charge. It must be pleaded orally, either by defendant or by his counsel, in the form not guilty by reason of insanity at the time of the alleged commission of the crime. A defendant who does not plead not guilty by reason of insanity shall be conclusively presumed to have been sane at the time of the commission of the offense charged, provided that the court for good cause shown may allow a change of plea at any time before the commencement of trial. A defendant who pleads not guilty by reason of insanity, without also pleading not guilty, thereby admits the commission of the offense charged.”
This provision is mandatory to the extent that it requires a defendant who intends to defend on the ground of insanity to interpose an appropriate plea. But this does not mean that the section operates to exclude every other possible mental examination of an accused. The provision does not seek to regulate arrest and investigation. Although the practice which was here *469followed could if misused be invalid, there is nothing in the statute which precludes the employment by either the accused or the People of physicians or psychiatrists with a view to their testifying at the trial.
C.R.S. ’53, 39-8-2 provides that immediately after the entry of a plea the accused shall be committed to the Colorado State Hospital at Pueblo or the Colorado Psychopathic Hospital in Denver for observation and examination. This is intended to insure examination by psychiatrists, specialists in mental diseases, during the period of observation, but like 39-8-1 it does not operate to exclude private employment of psychiatrists.
The statute cannot be construed as exclusive from the standpoint of the People and not exclusive when applied to the accused. Hence, the result of the interpretation urged by the defendant would be to bind the accused to the results of examinations by psychiatrists at the Colorado Psychopathic Hospital in Denver or the Colorado State Hospital in Pueblo. If these physicians were to find the accused insane he would then be powerless to secure and introduce contrary testimony. This strained and rigid interpretation is not justified by either the statutory provisions or by our decisions.
Though mandatory to the extent indicated above, the statute does not govern all aspects of the criminal insanity question. This is apparent from our holdings in Ingles v. People, 92 Colo. 518, 22 P. (2d) 1109; Battalino v. People, 118 Colo. 587, 199 P. (2d) 897; Berger v. People, 122 Colo. 367, 224 P. (2d) 228; Leick v. People, 131 Colo. 353, 281 P. (2d) 806. These cases stand for the proposition that evidence of insanity is relevant in a criminal trial, notwithstanding that defendant has merely entered a plea of not guilty, as bearing upon the capacity of the accused to form a specific intent. The rule was strongly reiterated in Beckstad v. People, 133 Colo. 72, 292 P. (2d) 189 as follows:
“* * * We regret that we must say once more that which has heretofore been said over and over again for *470the guidance of trial courts and prosecuting officers: A defendant in a first degree murder case has the right, without reference to a plea of insanity, to establish mental deficiency as bearing upon his capacity to form the specific intent essential to first degree murder. * * *”
Finally the principle was codified in 1955, C.R.S. 1953, 39-8-1 (Cum. Supp. 1957).
Weihofen, Mental Disorder as a Criminal Defense, 333, considers the question whether partisan experts could be validly excluded and whether a statute would be constitutional which creates exclusive procedures for examining the accused and for the giving of expert testimony. He points out that Wigmore, 3d Ed. §563 holds that such a statute interferes with the constitutional right of the parties to adduce such evidence as they think useful. He also points out one state has adopted a statute providing such exclusive provisions and that this had been held unconstitutional. See State v. Lange, 168 La. 958, 123 So. 639. (The statute in that case is somewhat more extreme in its provisions than excluding non-appointed expert witnesses.) Whether such a statute is valid need not be determined since our statute does not exclude other examinations or testimony based upon non-statutory examinations. The Weihofen and Wigmore discussions serve to point up the complexity of the problem and the confusion which would follow a holding that our statute excludes testimony other than that which originates pursuant to it.
Thus it cannot be said that the statute (39-8-2) here in question establishes exclusive procedures governing the mental examination of the accused. The emphasis of the statute is the establishing of procedures for pleading and trying (looking to a judgment of sane or insane) the insanity issue.
The underlying basis of defendant’s objection is that examinations of the'kind here conducted deprive him of a tactical advantage. He argues that if the prosecution is allowed to conduct a preliminary mental examination *471the defendant is thereafter practically compelled to enter a plea of not guilty by reason of insanity. He no longer has an option to plead not guilty anticipating that he can still offer evidence of insanity for the limited purpose of negativing malice or intent and at the same time foreclosing the prosecution from a mental examination. When, as here, the prosecution secures the insanity evidence at the very outset, it is prepared for this eventuality and the accused no longer has a monopoly on this type of proof. It is said the defendant is thus deprived of a defense which has been available to him.
This contention carries to an illogical extreme the adversary or contest aspect of the insanity trial, and we are unable to agree that the defendant is deprived of a right granted by statute or guaranteed by the constitution. A pre-arraignment mental examination of the accused does not of itself violate his rights any more than the taking of a statement from him constitutes a per se violation. It would follow, therefore, that the single serious issue which arises is whether the particular examination violates the constitutional rights of the accused.
II.
The question whether the pre-arraignment mental examination constituted a violation of defendant’s privilege against self-incrimination or deprives him of his life, liberty or property without due process of law.
Defendant argues that the examination (and subsequent testimony) of Drs. Rymer and Hilton violated his constitutional rights as defined by the Fourteenth Amendment of the Constitution of the United States and Article II, Section 18 of the Colorado Constitution in that he was compelled to testify against himself. Tuttle v. People, 33 Colo. 243, 79 Pac. 1035; Radinsky v. People, 66 Colo. 179, 180 Pac. 88; People v. Clifford, 105 Colo. 316, 98 P. (2d) 272; People v. McPhail, 118 Colo. 478, 197 P. (2d) 315, and People of the State of Colorado v. Schneider, 133 Colo. 173, 292 P. (2d) 982. Tliese cases recognize *472that the privilege against self-incrimination operates to protect the accused against compulsory testimony not only at the trial but also in other proceedings. In the Tuttle case the accused, though suspected of the crime, was called to testify under oath at the coroner’s inquest. In other cases the accused had been called to testify before grand juries. In Block v. People, 125 Colo. 36, 240 P. (2d) 512 the privilege was held to be inapplicable to real or demonstrative evidence. To the same effect is Kallnbach v. People, 125 Colo. 144, 242 P. (2d) 222.
Confessions of guilt are subject to exclusion if shown to have been involuntary and thus untrustworthy. See Osborn v. People, 83 Colo. 4, 262 Pac. 892; Buschy v. People, 73 Colo. 472, 216 Pac. 519; Cahill v. People, 111 Colo. 29, 137 P. (2d) 673. A showing that a confession is involuntary also renders it incompetent on the basis that it is in violation of the substantive due process requirement of the Fourteenth Amendment to the Constitution of the United States. See Watts v. Indiana, 338 U. S. 49; Turner v. Pennsylvania, 338 U. S. 62; Harris v. South Carolina, 338 U. S. 68, and see Downey v. People, 121 Colo. 307, 215 P. (2d) 892. These cases do not, however, hold that such statements violate the privilege against self-incrimination. The Supreme Court of the United States has held that the privilege against self-incrimination guaranteed by the Fifth Amendment, Constitution of the United States does not constitute a restraint on state action. Twining v. State of New Jersey, 211 U. S. 78. The involuntary confession is subject to the due process requirement of the Fourteenth Amendment because it is contrary to basic democratic concepts. In Lisenba v. California, 314 U. S. 219, 236, the reason for rule of exclusion is explained:
“* * * As applied to a criminal trial, denial of due process is the failure to observe that fundamental fairness essential to the very concept of justice. In order to declare a denial of it we must find that the absence of that fairness fatally infected the trial; the acts com*473plained of must be of such quality as necessarily prevents a fair trial. Such unfairness exists when a coerced confession is used as a means of obtaining a verdict of guilt. We have so held in every instance in which we have set aside for want of due process a conviction based on a confession. * * *”
There is no suggestion that the defendant’s responses in the case at bar were extorted from him by force, express or implied. Furthermore, there is no showing that the defendant was deceived or that he submitted to the interview-examination under the influence of material misapprehensions. Defendant has testified that he was not aware that he was receiving a mental examination when the psychiatrists interviewed him. He believed, according to his testimony, that the doctors were District Attorney agents. He does not say, however, that he would have remained mute had he been aware of their character. The doctors testified that they identified themselves as doctors. Moreover, there is basis for concluding that the defendant was aware of their identity as psychiatrists. Thus the doctrine of Rochin v. California, 342 U. S. 165, which condemns forcible invasion of the person of the defendant, cannot be applied here on the theory that this was a forcible or surreptitious mental invasion. We are of the opinion, therefore, that the defendant’s rights were not violated and that the trial court was correct in ruling that the testimony in question was not subject to suppression and was admissible in evidence.
III.
Is C.R.S., ’53, 40-2-3 unconstitutional in that it defines murder committed in the perpetration of a robbery as murder in the first degree?
Defendant argues that malice is an essential ingredient of the crime of murder at common law and under our statute and that the attempt by the legislature to substitute certain named felonies for proof of this element *474is invalid. He relies upon Garcia v. People, 121 Colo. 130, 213 P. (2d) 387, and Tot v. U. S., 319 U. S. 463.
In the Garcia case a statute was declared unconstitutional which provided that in a prosecution for larceny of cattle in which ownership is alleged to be unknown it is prima facie evidence of guilt that one who has butchered a meat animal has failed to produce the hide. The Court held that no rational relation was shown to exist between the failure to produce the hide and the presumed facts which embraced all of the essential elements of the crime of larceny, including the corpus delicti. The Tot case, supra, involved a,statute which provided that where a person had been convicted of a crime of violence and was thereafter found in possession of firearms, a presumption would exist that he had unlawfully transported the same in interstate commerce. It is readily apparent that these cases are distinguishable in that they involve use of the true presumption as a substitute for proof and dispense with the necessity for proving all the elements of the crime upon the basis of a fact which does not logically give rise to the conclusions involved in the particular offenses. In the present case, we do not have a true presumption. Here the legislature has provided a substantive definition of murder. It has declared that murder committed in the perpetration of the named felonies is murder in the first degree. The prosecution is required to prove the homicide beyond a reasonable doubt-and is also required to establish to the same degree of proof the commission of the named felony and the commission of the homicide in the perpetration of the said felony.
It was competent for - the General Assembly to adopt this definition and the rule described in the above cases, which is also discussed in Melville, Manual of Criminal Evidence 44, is not applicable. See Wigmore, 3d Ed. §2492 (holding that this type of legislative definition does not constitute a presumption).
Our cases have uniformity upheld the provision in *475question. Andrews v. People, 33 Colo. 193, 79 Pac. 1031; Jones v. People, 93 Colo. 282, 26 P. (2d) 103; Frady v. People, 96 Colo. 43, 40 P. (2d) 606; Leopold v. People, 105 Colo. 147, 95 P. (2d) 811. In Silliman v. People, 114 Colo. 130, 162 P. (2d) 793, the Court briefly considered the specific point which is here posed and summarily - disposed of it as follows: (114 Colo. 144.)
- “The court advised' the jury in one of its instructions that if the defendant t!|! * * committed the homicide charged in the information * * * by means of poison * * * malice, deliberation, premeditation, and intent * * * need not be proved.’ Defendant apparently takes the position that irrespective of the method of effecting a homicide, malice, deliberation, premeditation and intent must be proved. The most casual reading of our decisions will convince one that this contention is without legal support. Andrews v. People, 33 Colo. 193, 79 Pac. 1031; Jones v. People, 93 Colo. 282, 26 P. (2d) 103; Brady v. People, 96 Colo. 43, 40 P. (2d) 606.”
In Jones v. People, supra, it was held that murder in the second degree is not an issue where there are no facts in the record justifying submission of instructions and a verdict defining second degree murder. The specific pertinent language of Mr. Justice Butler is as follows: (93 Colo. 288.)
•J“Where murder is committed by means of poison or lying in wait, or in the perpetration of, or in an attempt to perpetrate, one of the felonies specified, in section 665, supra,' there is only one degree of murder, namely, murder of the first degree. If the uncontradicted evidence is to the effect that murder was committed in one of the ways specified above, .and in no other way, the question of second degree murder is not in the case, and the defendant should be found guilty of murder of the first degree, or he should be acquitted; there is no middle course.” ■ .
See also Battalino v. People, 118 Colo. 587, 199 P. (2d) 897 which upheld a verdict of first degree murder and *476also ruled that it was not error under circumstances very-similar to those presented here to refuse to submit a verdict of second degree murder.
It follows that the statute is valid and that the court was correct in its refusal to submit murder in the second degree to the jury.
IV.
Validity of the right and wrong and irresistible impulse tests described by C.R.S. ’53, 39-8-1 (2).
This phase of defendant’s argument addresses itself to the right and wrong test. It urges that this, together with the irresistible impulse test is outmoded and that it should be repudiated in favor of the tests which are approved in Durham v. U. S., 214 F. (2d) 862. We have previously considered this contention and have rejected it in Castro v. People, decided November 2, 1959, 140 Colo. 493, 346 P. (2d) 1020. See also Wechsler, The Criteria of Criminal Responsibility, 22 U. of Chicago L. Rev. 367, 374, etc.
We have carefully examined the record and find it to be remarkably free of error. The defendant was represented by highly competent counsel who defended him with skill and ability, and we cannot say that he did not receive a fair trial.
The judgment is affirmed and it is ordered that the same be executed during the week beginning June 20, 1960.
Mr. Justice Day and Mr. Justice Moore dissent.