We first consider defendant’s argument that there was insufficient evidence to show that he killed Ms. Hennessee with premeditation and deliberation.
In order for the trial court to submit a charge of first degree murder to the jury, there must have been substantial evidence presented from which a jury could determine that the defendant intentionally shot and killed the victim with malice, premeditation and deliberation. State v. Horton, 299 N.C. 690, 263 S.E. 2d 745 (1980); State v. Heavener, 298 N.C. 541, 259 S.E. 2d 227 (1979); State v. Baggett, 293 N.C. 307, 237 S.E. 2d 827 (1977). “Substantial evidence” is that amount of relevant evidence that a reasonable mind might accept as sufficient to support a conclusion. State v. Smith, 300 N.C. 71, 265 S.E. 2d 164 (1980); State v. Powell, 299 N.C. 95, 261 S.E. 2d 114 (1980). In ruling upon defendant’s motion to dismiss on the grounds of insufficient evidence, the trial court is required to interpret the evidence in the light most favorable to the State, drawing all reasonable inferences in the State’s *84favor. State v. Fletcher, 301 N.C. 709, 272 S.E. 2d 859 (1981); State v. King, 299 N.C. 707, 264 S.E. 2d 40 (1980).
Premeditation has been defined by this Court as thought beforehand for some length of time, however short. No particular length of time is required; it is sufficient if the process of premeditation occurred at any point prior to the killing. State v. Myers, 299 N.C. 671, 263 S.E. 2d 768 (1980); State v. Reams, 277 N.C. 391, 178 S.E. 2d 65 (1970); State v. Robbins, 275 N.C. 537, 169 S.E. 2d 858 (1969). An unlawful killing is committed with deliberation if it is done in a “cool state of blood,” without legal provocation and in furtherance of a “fixed design to gratify a feeling of revenge, or to accomplish some unlawful purpose.” State v. Faust, 254 N.C. 101, 106-07, 118 S.E. 2d 769, 772 (1961). The intent to kill must arise from “a fixed determination previously formed after weighing the matter.” State v. Exum, 138 N.C. 599, 618, 50 S.E. 283, 289 (1905). See also State v. Baggett, supra; State v. Britt, 285 N.C. 256, 204 S.E. 2d 817 (1974).
Id. at 296-97, 278 S.E. 2d at 223.
Premeditation and deliberation are mental processes and ordinarily must be proved by circumstantial evidence. State v. Corn, supra; State v. Calloway, 305 N.C. 747, 291 S.E. 2d 622 (1982). Among the circumstances which may be considered as tending to show premeditation and deliberation are: (1) the want of provocation on the part of the victim, (2) the defendant’s conduct and statements before and after the killing, (3) threats made against the victim by the defendant, (4) ill will or previous difficulty between the parties, (5) evidence that the killing was done in a brutal manner. See State v. Calloway, supra; State v. Potter, 295 N.C. 126, 244 S.E. 2d 397 (1978); State v. Thomas, 294 N.C. 105, 240 S.E. 2d 426 (1978). The nature and number of the victim’s wounds is also a circumstance from which an inference of premeditation and deliberation may be drawn, State v. Brown, 306 N.C. 151, 293 S.E. 2d 569, cert. denied, --- U.S. ---, 103 S.Ct. 503, 74 L.Ed. 2d 642 (1982), as is the number of blows inflicted upon the victim. State v. Love, 296 N.C. 194, 250 S.E. 2d 220 (1978); State v. Thomas, supra.
The State’s evidence tended to show that defendant made statements to three witnesses in which he stated the manner and *85motive for the murder of Ms. Hennessee. He told the witness Smith that the victim “was supposed to get some pills for him, Preludin, and he went up and she didn’t have them and she got freaked out and he beat her with a brick.” He in substance repeated the statement to Smith some six months later. Defendant also made a statement to the witness Mary Frances Pickens that he “killed the white woman with a brick.” He indicated to Ms. Pickens that he killed Ms. Hennessee because she did not give him “some drugs” and further because he thought “she had some money.” Testimony of the witness Lloyd was to the effect that defendant told her he dressed up like a woman and went to the home of the victim and beat her to death with a brick.
This evidence alone was sufficient to carry the case to the jury on the question of premeditation and deliberation. It is true that the credibility of these witnesses was questionable, but the credibility of the witness is a question for the jury. State v. McQueen, 295 N.C. 96, 244 S.E. 2d 414 (1978). Further, the State’s evidence as to premeditation and deliberation was strengthened by the physical evidence found at the scene and the testimonial evidence of Dr. Hudson. This evidence tends to show that the victim was repeatedly struck about the head with a brick with such force as to break the brick into two pieces. Two of the blows were of such force that either of them could have caused death within a short time.
Blood consistent with Ms. Hennessee’s blood type was splattered throughout the rondette and there was blood on the bottom of her feet. These facts support an inference that the victim attempted to flee and her assailant pursued and continued his attack. The brutality of the murder is accentuated by the fact that there was evidence tending to show that prior to the victim’s death there was an attempt to smother her. Further, there was no evidence of provocation on the part of Ms. Hennessee.
This sustained and brutal attack without provocation on the part of the victim, together with the testimonial evidence, amply supported a jury finding that defendant acted in accordance with a fixed design or that he had sufficient time to weigh the consequences of his action.
We therefore hold that there was sufficient evidence to support a jury finding of premeditation and deliberation.
*86  We next turn to defendant’s contention that the trial judge committed prejudicial error in his instructions to the jury. He specifically maintains that the following portion of the instructions was erroneous:
Members of the jury, there’s evidence which tends to show the Defendant stated to Mr. Matthews that on the date in question, the 21st of February, 1975, that he and Pearcy went to the rondette on Howland Road and that he kept a dental appointment with Dr. Love and that he picked up his wife at work and remained home. Now, there’s been further evidence from Dr. Love which says the Defendant’s first appointment with Dr. Love was on March 24, 1975. Now, members of the jury, if you find from this evidence that the Defendant was not where he professed to be on February 21, 1975 and you so find beyond reasonable doubt, and that this was done to divert suspicion from himself, then you may give such weight as you find it’s reasonable to do.
This portion of the instruction was requested by the State and was given over defendant’s objection.
It is established by our decisions that false, contradictory or conflicting statements made by an accused concerning the commission of a crime may be considered as a circumstance tending to reflect the mental processes of “a person possessed of a guilty conscience seeking to divert suspicion and to exculpate [himself].” State v. Redfern, 246 N.C. 293, 297-98, 98 S.E. 2d 322, 326 (1957). The probative force of such evidence is that it tends to show consciousness of guilt. Id. See also State v. Yearwood, 178 N.C. 813, 101 S.E. 513 (1919); State v. Gillis, 15 N.C. 606 (1834).
The State takes the position that defendant was not prejudiced by the challenged instruction since the instruction failed to tell the jury that the false statements could be considered as evidence tending to show consciousness of guilt on the part of defendant. The State maintains that the instruction was in fact favorable to defendant since the jury was instructed to give this evidence “such weight as you find it’s reasonable to do.” At first glance, the State’s argument seems plausible and the instruction itself appears to be rather innocuous. However, upon a closer study of the rationale of the cases permitting evidence of falsehoods or contradictory statements as showing consciousness *87of guilt, and an application of that law to the facts of this case, we must reject the State’s argument.
In State v. Redfern, supra, the defendant was charged with murder. The defendant made various conflicting statements about how the deceased met his death at the scene of the crime. This Court held that “[t]hese conflicting statements voluntarily made at the scene of the homicide, tend to reflect the mental processes of a person possessed of a guilty conscience seeking to divert suspicion and to exculpate herself. This line of testimony was substantial evidence of substantial probative force, tending to show consciousness of guilt.” 246 N.C. at 297-98, 98 S.E. 2d at 326 (emphasis added) (citations omitted).
State v. Yearwood, supra, involved an alibi. There the defendant’s mother, in his presence and with his assent, stated that the defendant was in bed at the time the alleged crime was committed. There was evidence that he was seen away from home at that time. The Court held that these facts were circumstances tending to show guilt since defendant was impliedly asserting an alibi which was contradicted by other evidence.
Our research discloses that “consciousness of guilt” may be established, inter alia, by evidence of flight on the part of an accused.2 We are of the opinion that the rules of law governing flight which show consciousness of guilt are equally applicable to evidence of falsehood. We therefore find it helpful to consider the evidentiary effect of flight by an accused.
In North Carolina, evidence of flight does not create a presumption of guilt but is some evidence which may be considered with other facts and circumstances in determining guilt. However, proof of flight, standing alone, is never sufficient to establish guilt. State v. Irick, 291 N.C. 480, 231 S.E. 2d 833 (1977). Further, evidence of flight may not be considered as tending to show premeditation or deliberation. State v. Payne, 213 N.C. 719, 197 S.E. 573 (1938); State v. Marsh, 234 N.C. 101, 66 S.E. 2d 684 (1951).
*88In instant case, we find the challenged instruction erroneous because it permitted the jury to roam at will without making it clear that the falsehood did not create a presumption of guilt or that, standing alone, such evidence was not sufficient to establish guilt. Neither did the trial judge inform the jury that such evidence could not be considered as tending to show premeditation and deliberation.3 Furthermore, the statements referred to in the instruction under scrutiny were completely irrelevant since the alleged falsehood referred to defendant’s whereabouts during the morning hours of 21 February 1975 and all the evidence was to the effect that the crime occurred in the afternoon of that day.
Having concluded that the instruction was erroneous, we consider whether the instruction before us was of such prejudice as to require a new trial.
G.S. 15A-1443(a) states the test for prejudicial error to be whether there is a “reasonable possibility that, had the error in question not been committed, a different result would have been reached at the trial . . . .” The burden of showing prejudice is upon the defendant. State v. Easterling, 300 N.C. 594, 268 S.E. 2d 800 (1980).
The evidence in the case before us was entirely circumstantial. None of the investigatory or scientific evidence tended to point to defendant as the perpetrator of the crime. Witnesses upon whom the State relied to furnish the facts from which inferences of defendant’s guilt were drawn were of extremely questionable credibility. Although we are of the opinion that the evidence was sufficient to survive a motion to dismiss, all of the circumstances present a very close question as to defendant’s guilt or innocence. In addition to the matters hereinabove set forth, the trial judge’s emphasis upon the negative aspect of defendant’s statements to the police officers may well have left the jury with the impression that he did not find defendant’s statements to be credible. See State v. Byers, 80 N.C. 426 (1879).
For these reasons, we are of the opinion that there was a reasonable possibility that a different result would have been *89reached had the erroneous instruction not been given. We therefore hold that this erroneous instruction requires a new trial.
In the present posture of this case, we do not deem it necessary to discuss defendant’s contention that the trial judge improperly expressed an opinion by calling the witness, Dr. Love, to the bench at the conclusion of his testimony and engaging in a brief conversation with the doctor. Suffice it to say that the trial judge must not by words or conduct suggest an opinion as to the weight of the evidence or as to the credibility of a witness. State v. Belk, 268 N.C. 320, 150 S.E. 2d 481 (1966).
For the reasons stated, there must be a