delivered the opinion of the Court.
The Superior Court, San Juan Part, having dismissed the petition for Habeas Corpus on the ground that appellant did not have adequate assistance of counsel in a case of murder and carrying of weapons, appellant assigns that Said court erred in determining that petitioner had adequate *187assistance of counsel at the hearing of said cases on June 12, 1962, which resulted in his conviction of murder in the second degree and carrying of weapons. The facts which gave rise to the accusations in this case occurred on April 24, 1961. The judgment was rendered on June 18, 1962.
The circumstances of the case recited below show that he is wrong.
At the outset of the hearing of the case of murder in the first degree and carrying of weapons, appellant’s counsel requested that the expert witnesses, who a month before had determined that appellant could stand trial, examine him again. They did so and informed that he could stand trial. Having waived his right to a trial by jury, appellant pleaded guilty of murder in the second degree. The incident on this particular was as follows:
“Prosecuting Attorney:
With the leave of the court. We want to inform that the People will prosecute the case as murder in the second degree.
Judge:
Plea, then?
Mr. Juliá:
Hon. Judge, that being the situation, defendant shall plead through us, guilty of murder in the second degree.
Judge:
Q. Rigoberto, have you heard the plea, made by your attorney, of guilty of murder in the second degree?
A. Yes, sir.
Q. Do you subscribe to the words of the attorney?
A. Yes, spontaneously.
Q. Have you been forced or coerced by anybody?
A. Absolutely by no one.
Q. Has anybody promised you benefit or reward?
A. No, sir.
Q. Have you discussed your case with Mr. Juliá and do you agree with your attorney that you are guilty of murder in the second degree?
A. Yes, sir.
*188Q. Do you know that you were entitled to the presentation of evidence against you and then you could present your evidence if you had any?
A. Yes, sir.
Q. Do you waive that right and admit that you are guilty of the offense?
A. Yes, Hon. Judge.
J. Colleague, there is also case No. M-61-823, a misdemeanor.
Mr. Juliá:
Let us consider the charge in relation to the carrying of weapons as read, to which he also pleads guilty.
Judge:
Q. Rigoberto, did you hear the plea of guilty made by your attorney in this case where you are charged that on April 24, 1961 you carried a knife, which you used to commit a murder?
A. Yes, sir.
Q. And do you agree ?
A. Yes, sir.
Q. And you make the plea voluntarily?
A. Yes, sir.
Q. Has anybody threatened you to plead guilty?
A. Absolutely no one.
Q. Has anybody made promises ?
A. Nobody.
Q. Have you discussed the case with your attorney, Juliá, and do you agree that actually you are guilty of said facts?
A. Yes, sir.”
For the purpose of supporting his assignment, appellant makes a summary of the evidence presented at the hearing of this case in the trial court. Let us see our own recital of the same.
Witness José O’Ferral Santos, custodian of records of the Veterans’ Administration, testified that from appellant’s records, which he had before him, it appeared that in 1949 appellant was confined in Clínica Juliá suffering from schizophrenia. He was granted a 100% disability. Later he went to the neuropsychic clinic of the Veterans’ Administration for ambulatory treatment. He was confined in Clínica Juliá *189from March 7 to 11, 1961. The diagnosis resulting from the psychiatric examination performed in 1956 was “Psychotic reaction, psychotic personality.” Identical diagnosis was made in 1955. The last one, in 1963 was “Schizophrenic reaction, catatonic . . . .”
Appellant’s testimony has been properly summarized by the Solicitor General with some modifications we have made as follows:
Molina Santana testified that he is a veteran and that he is receiving a pension corresponding to 100% disability. He testified that originally he was accused of murder in the first degree; that he retained the professional services of Mr. Charles H. Juliá to represent him at the trial “some time after” he was accused and after he was on bail. The bail was admitted on August 14,1961. He visited his attorney several times in his offices, in the Capitol, tie had talked to his attorney several times near the court, and although he went several times to see him, he could only see him on one occasion, when he conferred with him and on which occasion he said he had paid for his services. He affirmed that the case was continued on several occasions, but that he never came to an agreement with the attorney in relation to the issue of the case. He stated that he informed his attorney that he had a witness, and that he had asked the former to summon him, but the attorney told him that it was unnecessary.
Petitioner affirmed that he was not satisfied with his attorney’s services because notwithstanding petitioner having asked his attorney to summon the physicians of the Veterans’ Administration, he did not do it, nor did he procure the presentation of petitioner’s records kept in the civil courts. Finally he testified that he pleaded guilty because his attorney had told him to do so and because “Dr. Galindez told me to take his advice because I would rot if I were pronounced crazy”; that he knew in advance the sentence they would impose on him, and because the psychiatrist himself advised *190him that it was better to be sentenced to 10 or 15 years than to remain confined in the insane asylum for life. Although he pleaded guilty he never felt he was guilty. In support of such a statement he invoked his mental condition, “because he saw and heard animals behind him saying ‘dead or alive’ and that is why he fired and when he woke up in his house he was informed that he had killed a person.” However, he said he did not realize what had happened.
Mr. Juliá testified that:
He has been practicing law for thirty years. He met defendant when he went to retain his services to represent him in a case of murder. He conferred with petitioner on one or two occasions. The case had been continued several times and the attorney became acquainted with the fact that defendant had been under psychiatric treatment. He interviewed prosecuting attorney Torres González, who informed him that he had ordered a psychiatric examination immediately after the occurrence of the facts.
Mr. Juliá testified that defendant had recited to him his own version of the facts. He asked defendant whether he had witnesses and Molina Santana told him that he did not have any. According to what defendant informed him he had arrived at a public establishment with a knife; that a person had asked defendant to deliver the knife to him and that defendant had challenged him to take it away from him. That they started to wrestle and that as the person fell down he was wounded. The investigation performed by the attorney showed that the facts were different. The witnesses for the prosecution maintained that defendant had appeared at the premises with a knife, and without any interchange of words he stabbed the victim through the stomach.
He said that as soon as he became acquainted with the history of the case, he took steps in order that appellant be submitted to a psychiatric examination and insisted that *191Dr. Señeriz form part of the examining panel, since he had been appellant’s attending physician. Said panel concluded that appellant “could stand trial.” He remembered having seen a psychiatrist’s report to the effect that at the time of the occurrence, appellant was not mentally incompetent; but he did not recall his name. He explained that appellant went to retain his services many months after the occurrence of the facts. He admitted that a person who can stand trial at the time of the hearing may not have been sane at the time of the commission of the facts. When asked whether it was possible that two months subsequent to the act a psychiatrist could examine a person on the basis of his previous medical record and determine that it is possible that said person was suffering a mental disorder when the acts were committed, he answered that according to his experience the psychiatrists would report that it was not possible. He said that in his opinion “when the psychiatrists said that the man could stand trial, it discards the theory of insanity.”
Dr. Galindez, one of the psychiatrists who on several occasions examined appellant, testified that he examined him in April 1962 and that on four occasions he examined him together with psychiatrists Valderrábano, Señeriz and Te-jedor, for the purpose of determining whether he could stand trial. He reached the conclusion that appellant was suffering from a schizophrenic reaction, paranoid in the remission of symptoms, this meaning that “The symptoms characterizing this [the mental disorder] have disappeared.” When asked whether he could “determine whether by the year 1961 that person [appellant] could be under the effect of a doubtful mental condition,” he answered:
“Undoubtedly. To answer that question I would certainly have to base my answer on a direct-psychiatric examination' the most recent examination; if this examination had been performed immediately after the commission of the offense, I could tell with more certainty and more scientifically, whether *192said person was suffering this or that condition. Generally, I could tell you that he could or could not be sick.
Q. For example, that his mental condition would be such that he could not distinguish between right and wrong?
A. That possibility exists for everyone.
Q. You could not make that determination now nor could have made it that day?
A. To go back to ’61, no. I say, he has a medical record, I imagine there is a record of the doctors who examined him, I imagine. I could not . . . .”
In People v. Sánchez, 79 P.R.R. 110 (1956), we said that defendant’s insanity at the time of committing the criminal act is what exempts him from criminal liability; that his behavior before or after the commission of the acts does not prove that he was insane at the time he committed them; that the expert testimony as to defendant’s mental condition after the commission of the criminal act is admissible in support of the defense of insanity, but when the testimony of an expert challenges the credibility of another expert, “it is incumbent on the jury to determine . . . which testimony to believe”; that the opinion of an expert witness is not binding upon the triers and that in weighing expert evidence the court is not bound to accept the opinions of an expert.
In People v. Alsina, 79 P.R.R. 44 (1956), we adopted the following rule:
“In our opinion, the rule of evidence which should govern when the question of insanity is raised to excuse from responsibility is this: The law presumes that sanity is the normal condition, a presumption which is justified by human experience and by considerations of public policy, and, hence, that the defendant was of a sound mind when he committed the act charged as an offense. By virtue of that presumption, The People is not required to offer any evidence to show that the defendant was sane at that moment, unless evidence is offered and received which may create a reasonable doubt as to sanity, which evidence must be furnished by the defendant if he relies on the absence *193of mental soundness for exemption from responsibility-, but which may also develop from the evidence offered by The People when presenting its case .... However, once there is evidence capable of creating that doubt, the presumption that the defendant was sane at the time of committing the act is overcome and the State is required to prove sanity as well as any other fact. After weighing the entire evidence as to the act charged and as to insanity, the trier is required to determine whether the prosecution has established defendant’s sanity, his capacity to commit a crime, and, if it then entertains reasonable doubt, it is under the duty to give the benefit of that doubt to the defendant and to acquit him.”
Although expert evidence relating to defendant’s mental derangement some time prior or subsequent to the commission of the acts is admissible to prove the latter’s mental incompetency at the time when he committed them, in determining its weight and credibility the trier can take into consideration the time elapsed between the date on which his condition was determined and the date of the offense. Harriford v. Harriford, 336 S.W.2d 113, 117 (Mo. 1960); State v. Duncan, 93 S.E.2d 421, 423 (N.C. 1956); Poole v. State, 207 S.W.2d 725 (Ark. 1948); People v. Preston, 173 N.E. 383 (Ill. 1930); Sherill v. State, 225 Pac. 840 (Col. 1924); People v. Gavrilovich, 106 N.E. 521 (Ill. 1914); Swedley v. Commonwealth, 127 S.W. 485 (Ky. 1910); State v. McMurray, 58 Pac. 961 (Kan. 1899); People v. Hill, 195 N.Y.S.2d 295, 299 (1960).
In the light of the foregoing, appellant’s counsel did not neglect his responsibility in the case of murder by failing to allege the defense of insanity. It is true that appellant had a record of schizophrenia since long before the day of the occurrence of the facts.
For the purpose of establishing the defense of insanity, the best available evidence is the expert opinion of mental derangement resulting from an examination of the defendant “immediately after the commission of the offense,” *194as Dr. Galíndez testified. Said physician testified that if the examination is performed too late, it can only be said “that he could or could not have been insane.” Cf. People v. Rivera Raquel, 95 P.R.R. 553 (1967). Instead of such evidence the attorney had knowledge that the available evidence was that, at that time he was sane, as we indicate hereinafter.
On the contrary, in relation to the information on which the attorney for the defense relied for his determination to advise appellant to plead guilty of murder in the second degree, the examination of the attorney for the defense shows the following:
“Q. Did the psychiatrists in any manner make any report in which they declared that defendant was sane on the date of the commission of the offense?
A. No, but there is a report of a psychiatrist, I cannot recall who he was, it is a report I saw, which, as I said, my colleague Torres González courteously showed to me, a psychiatrist who was treating defendant at the time of the occurrence of the facts, saying that he was not mentally incompetent.
Q. You do not know who the doctor is ?
A. I cannot remember.
Q. Who ordered that examination?
A. My colleague Roberto Torres González, who was the prosecuting attorney who investigated these cases right after the occurrence.
Q. Do you know whether at any time, having knowledge that this citizen was entitled to veteran benefits, were any steps taken to submit him to an examination by a doctor of the Veterans’ Administration?
A. Yes, upon defendant’s insistence I, in turn, insisted that Dr. Sefieriz form part of the panel of expert psychiatrists; although said physician is a private-clinic physician he has a contract with the veterans.
Q. I mean immediately after the commission of the offense or immediately after he went to talk with you the first time.
A. No, because when defendant came to see me the first time, if I remember correctly, several months had already elapsed, *195I should say, about three or four months after the occurrence of the facts, so that when he came to see me the prosecuting attorney had already procured the services of a psychiatrist immediately after the occurrence of the facts.
Q. Do you know how long after the investigation made by prosecuting attorney Torres González petitioner was examined by the former’s psychiatrist?
A. From the commission of the offense until what examination?
Q. Until the examination ordered by him.
A. As far as I can remember, if I remember correctly, I am speaking from memory, he was examined by the physician designated by my colleague Torres Gonzalez.
Q. Do we have that report at hand?
A. I saw it about the year 1962, where it may be or who may have it, I do not know.
Q. Then, you trusted that examination of the prosecuting attorney’s physician?
A. It is not that I trusted it; I requested a psychiatric examination on three occasions; the fact is that said examination was performed on the day of the occurrence of the facts and I took the case several months later, which might have been two, three, four, I cannot remember, but it was several months later.
A. My experience has been, for example, I am going to cite you the case, specifically; when I defended Castañeda I raised the question of insanity and the clinical record was presented which was very similar to that of this defendant, a subsequent clinic-mental record and the psychiatrists plainly said in court that they could not tell whether - or not at the time Castañeda entered the jewelry shop he was crazy; and this is one of the cases I can remember, and then I have talked and discussed it with Dr. Sefieriz himself, and with Dr. Galind'ez, and all of them agree on this point.
Q. As an attorney in this contention, would he be guilty of murder in the first degree? ■
*196A. No, if guilty, he would be guilty of manslaughter and possibly of involuntary manslaughter, but what happens is that defendant’s theory stands alone against the staff of witnesses for the prosecution, who testified that the facts had occurred in a different manner, that there was no wrestling, and also there was a stab without provocation, that appellant had arrived and had stabbed that person with a knife and had killed him.
Q. And accepting said facts and having a medical record of that nature, from ’49 to ’63, as an attorney, was it not proper to think that said person was insane at that time?
A. Yes, except that I, as an attorney, not being a psychiatrist, had to rely on the opinion of the-psychiatrists, and the opinion of the psychiatrist who examined him immediately -after the occurrence of the facts was that he toas not mentally deranged, and the opinion of the expert witnesses later on also established that defendant could stand trial.” (Italics ours.) '
In the presence of clear and abundant evidence of the commission of the offense, and the probability of not being able to adduce robust and credible evidence in the sense that appellant was mentally deranged at the time of the commission of the offense, and therefore, considering the risk that appellant might be found guilty of murder in the first degree, we cannot conclude that his assistance of counsel was inadequate in presenting the plea of guilty, which appellant accepted and ratified at the hearing of the trial, when the medical experts, after examining him several times, certified that the symptoms of his previous mental condition had disappeared and that appellant could stand trial.
In the light of the circumstances previously recited, we cannot conclude that in this casé there was a fundamental negation of justice. The constitutional right of assistance of counsel which provides defendant a fair trial does not mean that every error of judgment or of strategy of trial tactics, or common error of policy in relation to the applicable law deprives defendant of said constitutional right. The record does not show that the attorney for the defense failed to exert himself to procure evidence as to appellant’s *197mental condition or to have him examined by a psychiatrist or to procure evidence of other possible defenses of which he might have knowledge, or that in exercising his judgment he did it without being duly informed of the circumstances of the case. United States v. Fay, 348 F.2d 705, 707 (2d Cir. 1965); Hickock v. Crouse, 334 F.2d 95, 100 (10th Cir. 1964); Brubaker v. Dickson, 310 F.2d 30, 37 (9th Cir. 1962). See also, Stack v. Bomar, 354 F.2d 200 (6th Cir. 1965).
Therefore, the order of the Superior Court, San Juan Part, entered in this case on August 12,1964, will be affirmed.
Mr. Chief Justice Negrón Fernández did not participate herein. Mr. Justice Santana Becerra dissented in a separate opinion in which Mr. Justice Hernández Matos and Mr. Justice Dávila concur.—O—