This is an appeal from judgment of sentence dated September 24, 1981. Appellant, Charles Frisbie, raises two issues for our consideration. The first issue is whether the trial judge erred in ruling that the evidence presented at appellant’s trial was not sufficient to put appellant’s sanity in issue. The second issue is whether the trial judge erred in sentencing appellant to one year probation on each of nine counts of recklessly endangering another person when these charges arose out of an automobile accident resulting from one unlawful act. Of these two issues, we find only the second to be meritorious. We therefore vacate the sentences imposed below on all counts of recklessly endangering another person and remand for resentencing.
Appellant was arrested on May 2, 1980. The circumstances of his arrest were as follows. At 5:00 p.m., two police officers noticed appellant’s vehicle proceeding west on Tasker Street in Philadelphia in an erratic manner. It seemed that appellant’s vehicle was continually stopping and moving forward in a jerking motion. Upon concluding that something was wrong, one of the officers, Elden Olsten, approached appellant’s vehicle while signaling appellant to pull over. Appellant locked his doors and rolled up his windows. He then reclined in his seat, putting his hands behind his head, and smiled. The appellant drove off. Officer Olsten returned to the police van. Upon his return *172he indicated to his partner that appellant seemed “spaced out” and that they were going to have trouble with him.
Because of traffic, the officers were compelled to follow directly behind appellant until they reached Broad and Tasker Streets. At this point Officer Olsten approached appellant’s vehicle again, but before he could break the window to gain entry into the interior of the vehicle, appellant propelled his vehicle forward, through a crowd of people in the street waiting for a trolley. Several persons suffered injury.
Appellant then entered the Schuylkill Expressway pursued by a second police van. A high speed chase ensued. On three occasions during the chase, the police officers narrowly avoided colliding with appellant’s vehicle when it veered in front of them. Finally, appellant lost control of his vehicle and it overturned on the expressway. Whereupon, appellant was apprehended.
After several months of delay because appellant was incompetent to stand trial, appellant was tried before the Honorable Alfred J. DiBona, Jr., sitting without a jury, on nine counts of recklessly endangering another person1 and one count of leaving the scene of an accident involving personal injury.2 His sole defense at trial was that he was legally insane in accordance with the M’Naghten test3, when he committed the offenses charged. After two days of trial, appellant was convicted on all counts. Post-verdict motions were filed and later denied. Appellant was then sentenced to one year probation on each of the criminal counts of which he was convicted. This appeal followed.
*173I.
Appellant argues that sufficient evidence was presented at his trial to raise the issue of insanity. He argues further that the Commonwealth had the burden of proving his sanity beyond a reasonable doubt4; and that it failed to discharge that burden. In light of Commonwealth v. Thompson, 274 Pa.Super. 44, 417 A.2d 1243 (1979), appellant’s arguments must be rejected.
The crux of the problem in the instant case is that the defense presented testimony of appellant’s insanity and the Commonwealth made no effort to present evidence of appellant’s sanity, other than, perhaps, testimony concerning the circumstances of the incident and what it could elicit from cross-examination. Also, the trial judge did not find that appellant’s sanity had been proven beyond a reasonable doubt. Commonwealth v. Thompson, supra, analyzes similar circumstances.
In Thompson, the defendant testified at trial that he had no knowledge of the crime of which he was charged, and that if anyone participated in the crime, it was his “consciousness,” a separate person that died in Bucks County. Notwithstanding his testimony, the trial judge convicted defendant of burglary, robbery, criminal conspiracy, and aggravated assault. On appeal, the defendant argued that his testimony raised the issue of insanity, and accordingly the Commonwealth could no longer rely on any presumption of sanity, rather it had to prove his sanity beyond a reasonable doubt. In an opinion by JUDGE CAVANAUGH, this court said:
[cjertainly it would work an unreasonable mischief if at the conclusion of every case the court on request had to send an insanity issue to the jury on the insistence of the defendant that a view of all the evidence raises the issue and requires a determination of whether the Common*174wealth has proved sanity. It appears, then, that there must be a threshold determination by the trial judge to determine if ... the ‘evidence in the case from whatever source’ is sufficient to raise the issue of insanity.
Commonwealth v. Thompson, supra, 274 Pa.Super. at 49, 417 A.2d at 1246. Upon examining the defendant’s testimony, the court in Thompson found the testimony to be sufficiently relevant to a determination of the defendant’s sanity under the M’Naghten test that the issue of insanity had to be considered. JUDGE CAVANAUGH went on to state that:
[o]nce raised the issue becomes one for the factfinder. The initial question must be whether the issue has been creditably raised or whether it is simply an artifice. Of course, if the factfinder decides on initial examination that the evidentiary source of the insanity issue is wholly contrived, that it is a complete sham, the evidence is rejected and there is no insanity issue for the Commonwealth to meet____ In this non-jury case the trial judge in his opinion following post-trial motions stated: “the court found the defendants [sic] insanity testimony to be a complete sham. The story concocted by Thompson demonstrated his intelligence and his awareness of the situation.” This issue was an issue best decided by the factfinder and our examination of the record leads us to conclude that his finding should not be disturbed.
Id., 274 Pa.Superior Ct. at 50, 417 A.2d at 1246-47. JUDGE CAVANAUGH concluded that there had been no error committed below.
As we read Thompson, the trial judge will first determine that the evidence of insanity is relevant to a determination of the defendant’s sanity under the M’Naghten test. Then, even if the evidence is relevant and the Commonwealth has not introduced independent proof that a defendant was sane, the defendant is not necessarily entitled to be acquitted by reason of insanity. The factfinder upon examining the evidence of insanity and its source must determine if the issue of insanity is creditably raised. It *175may reject the evidence of insanity, the effect of which is to relieve the Commonwealth from having to adduce proof beyond a reasonable doubt that the defendant was sane. If that determination is amply supported by the record, it may not be disturbed on appeal.
The evidence at appellant’s trial consisted primarily of the Commonwealth’s witnesses, three police officers, and appellant’s sole witness, a psychiatrist, Dr. Perry Berman. Appellant argues that the testimony of two of the police officers and that of Dr. Berman was sufficient to raise the issue of insanity.
One of the police officers described appellant’s appearance as “spaced out” and stated that he had “glazed eyes”. Another testified that he spoke incomprehensibly and was belligerent when finally taken into custody. We acknowledge that their description of appellant lends support to the conclusion of Dr. Berman that appellant suffered from a mental illness when the incident occurred. However, mental illness alone does not constitute legal insanity. Commonwealth v. Demmitt, 456 Pa. 475, 321 A.2d 627 (1974). The essence of insanity under the M’Naghten test is a defendant’s ability to know the nature and quality of his actions or know whether they are wrong or right. The testimony of the police officers that appellant appeared “spaced out” with “glazed eyes” and acted belligerently sheds no light on whether appellant knew the nature and quality of his acts or knew they were wrong.
The principal evidence of appellant’s legal insanity was the testimony of Dr. Berman. Dr. Berman opined that at the time of the incident appellant “did not know the nature and quality of his acts nor did he know they were wrong,” because appellant suffered from manic-depressive psychosis. N.T. Volume II at 75 and 76. He testified that appellant was under the delusion that he was being guided by demonic forces, and that appellant believed that the crowd of persons that blocked his way on the date of the incident were not really “flesh and blood” human beings who could be injured or killed.
*176Judge DiBona in his opinion denying appellant’s post-verdict motions said “[t]his court, sitting as factfinder, found the testimony of the defense concerning the ability of the defendant to differentiate between right and wrong on the date of the incident to be unworthy of belief. Accordingly, there being no insanity issue for the Commonwealth to meet the defendant’s post-verdict motions on this ground was denied.”
Apparently, the trial judge totally discounted the testimony of appellant’s expert witness. In this respect, the instant case is somewhat different factually from Thompson. In Thompson, the trial judge rejected the defendant’s insanity evidence, his testimony, as concocted; whereas, here the evidence of insanity came from an expert, and could not be said to be concocted because it was founded upon a recent past history of mental illness. Nonetheless, we believe that Thompson applies where expert testimony was the principal evidence of insanity and it appears that the validity of the expert’s opinion is questionable in light of facts of record.
Applying the Thompson analysis to the instant case, we have examined the record to determine if it amply supports the trial judge’s decision to discount the testimony of Dr. Berman. We note first that Dr. Berman did not attend appellant near the time of the incident, rather in reaching his conclusions he relied upon reports detailing appellant’s past history of manic-depressive psychosis and appellant’s medical records following the incident, and an interview with appellant and1 others some seven months after the incident. With this information Dr. Berman was able to render an opinion with a strong degree of medical certainty that appellant was unable to know the nature and quality of his actions or know that they were wrong. Dr. Berman testified that appellant believed that the police were sent after him by demons. It appears that Dr. Berman believed that appellant’s delusion was so prevalent in his thinking that it prevented him from regarding the crowd of people who were in front of him, prior to the incident, as a real *177obstacle to his forward progress. However, during cross-examination Dr. Berman was unable to explain why appellant would be deluded as to the probable consequences of his act of driving into a crowd of people, and seemingly not have the same lack of appreciation of the nature and quality of his actions when shortly before the incident, he drove his vehicle along a busy street with the police directly behind him in pursuit, without striking another vehicle or person. He could not say why appellant could believe that the crowd of people before him were not real and, apparently believe, the automobiles that also impeded his progress for almost a half mile were real enough that he did not drive his vehicle into one of them. N.T., Volume II at 99. Other portions of the record support the conclusion that appellant knew the consequences of driving his vehicle into another object, be it human or an automobile. N.T., Volume II at 39-43. The record of Dr. Berman’s cross-examination further indicates that appellant told Dr. Berman that shortly before the incident, when the police initially attempted to stop him, he knew he had not done anything wrong. N.T. Volume II at 83 and 96. This statement indicates that appellant had the capacity to differentiate between right and wrong only a short time before the incident. Dr. Berman believed that if appellant did have such a capacity, he was unable to use it. We find that these aspects of Dr. Berman’s testimony severely undermined his conclusion that appellant did not know the nature and quality of his actions and that he was not able to differentiate between right and wrong.
As the arbiter of both the law and the facts, Judge DiBona was at liberty to reject the expert opinion of Dr. Berman as insufficient to raise the issue of insanity for it, like any other evidence, is for the trier of fact to consider and to determine what weight, if any, it could be given. See Commonwealth v. Hicks, 483 Pa. 305, 396 A.2d 1183 (1979). We are satisfied that an adequate basis existed in the record to permit the trial judge to discount Dr. Berman’s opinion altogether, thus eliminating the only pertinent evidence of appellant’s legal insanity. See Common*178wealth v. Norman, 259 Pa.Super. 301, 393 A.2d 837 (1978) (Opinion in Support of Affirmance by Cercone, P.J. joined by Price, J. and Van der Voort, J.)
Absent creditable evidence of appellant’s legal insanity when the incident occurred, the issue of insanity had no substance. With the rejection of Dr. Berman’s testimony, the Commonwealth had no burden of producing evidence that would convince the trial judge that appellant was sane beyond a reasonable doubt.
II.
Appellant’s second issue challenges the legality of the sentences imposed upon him below. Appellant contends that it was error for the trial judge to sentence him to' consecutive one year terms of probation on each of nine counts of recklessly endangering another person, when all of these counts stem from a single unlawful act committed by appellant.5 Our examination of the Pennsylvania case law leads us to conclude that only one sentence may be imposed upon appellant.
In Commonwealth v. Walker, 468 Pa. 323, 362 A.2d 227 (1976), our supreme court stated that the:
[Ajnalysis of duplicitous sentence questions has traditionally revolved around the concept of injury to the sovereign, in this case the Commonwealth. One of the purposes of the criminal law is to punish offenses against the Commonwealth, as defined by the Legislature, and it follows that, ‘[t]he criminal prosecution is for the injury done to the Commonwealth, and not for the injury done to the individual who may, if entitled, obtain redress through a civil action. Where there is but one act of cause of injury, or death of a number of persons, there is *179but one injury to the Commonwealth, but where the acts or causes are separate, they are separate injuries to the peace and dignity of the Commonwealth... ’
Id. 468 Pa. at 331, 362 A.2d at 231 (citations omitted). When there has been a single injury to the “peace and dignity of the Commonwealth,” it is beyond the power of a sentencing court to impose multiple sentences upon a defendant. Commonwealth v. Walker, supra; Commonwealth v. Reynolds, 256 Pa.Super. 259, 389 A.2d 1113 (1978); Commonwealth v. Speelman, 235 Pa.Super. 109, 341 A.2d 138 (1975); Commonwealth ex rel. Brockway v. Keenan, 180 Pa.Super. 78, 118 A.2d 255 (1955). See also Commonwealth v. Crocker, 280 Pa.Super. 470, 421 A.2d 818 (1980); Commonwealth v. Lezinsky, 264 Pa.Super. 476, 400 A.2d 184 (1979).
We have determined from the record that the nine counts of recklessly endangering another person lodged against appellant were founded on a single unlawful act committed by appellant. The record reveals that appellant propelled his vehicle forward through a crowd of persons causing injury to numerous persons simultaneously. While this single action of appellant may constitute more than one criminal cause of action for recklessly endangering another person, it may still support but one sentence. See Commonwealth v. Cox, 209 Pa.Super. 457, 228 A.2d 30 (1967). See also Commonwealth v. Speelman, supra. Accordingly, we will vacate the sentences imposed upon appellant for all counts of recklessly endangering another person.
Since we are uncertain whether the trial judge might have sentenced appellant differently had he known that the consecutive probations imposed were illegal, we will remand for resentencing in order to permit the trial judge an opportunity to reconsider sentencing. Commonwealth v. Lezinsky, supra. So ordered. Jurisdiction is relinquished.
POPOVICH, J., files a concurring and dissenting opinion.. 18 Pa.C.S.A. § 2705.
. 75 Pa.C.S.A. § 3742.
. The M’Naghten test of insanity relieves a defendant of criminal responsibility for his actions if at the time he committed a crime he was under "such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or if he did know it, that he did not know he was doing wrong.” Commonwealth v. Woodhouse, 401 Pa. 242, 164 A.2d 98 (1960).
. Once the insanity issue is raised by evidence from whatever source, the Commonwealth bears the burden of proving beyond a reasonable doubt that a defendant was sane at the time he committed a crime. Commonwealth v. Demmitt, 456 Pa. 475, 321 A.2d 627 (1974).
. Appellant failed to file a motion for reconsideration of sentence. This failure does not result in the waiver of this sentencing issue, because it concerns the lawfulness of the sentence. Commonwealth v. Walker, supra, 468 Pa. at 330 n. 3, 362 A.2d at 230 n. 3; see also Commonwealth v. DeCaro, 298 Pa.Super. 32, 444 A.2d 160 (1982); Commonwealth v. Walls, 248 Pa.Super. 335, 375 A.2d 125 (1977) aff’d, 481 Pa. 1, 391 A.2d 1064 (1978).