Here's the entire discussion of the topic in the Merkouris case.
Two Reasonable Theories Instruction
[15] It is next contended that the trial court erred in refusing to instruct the jury concerning its duty if the evidence was susceptible of two reasonable theories.
Defendant offered this instruction: "If the evidence in this case is susceptible of two constructions or interpretations, each of which appears to you to be reasonable, and one of which points to the guilt of the defendant, and the other to his innocence, it is your duty, under the law, to adopt that interpretation which will admit of the defendant's innocence, and reject that which points to his guilt.
"You will notice that this rule applies only when both of the two possible opposing conclusions appear to you to be reasonable. If, on the other hand, one of the possible conclusions should appear to you to be reasonable and the other to be unreasonable, it would be your duty to adhere to the reasonable deduction and to reject the unreasonable, bearing in mind, however, that even if the reasonable deduction points to defendant's guilt, the entire proof must carry the convincing force required by law to support a verdict of guilty beyond a reasonable doubt."
The court instructed the jury as follows: "A defendant in a criminal action is presumed to be innocent until the contrary is proved, and in case of a reasonable doubt whether his guilt is satisfactorily shown, he is entitled to an acquittal, but the effect of this presumption is only to place upon the State the burden of proving him guilty beyond a reasonable doubt. Reasonable doubt is defined as follows: It is not a mere possible doubt; because everything relating to human affairs, and depending on moral evidence, is open to
[46 Cal.2d 561] some possible or imaginary doubt. It is that state of the case which, after the entire comparison and consideration of all the evidence, leaves the minds of the jurors in that conviction that they cannot say they feel an abiding conviction, to a moral certainty, of the truth of the charge."
"Two classes of evidence are recognized and admitted in courts of justice, upon either or both of which, juries lawfully may base their findings, whether favorable to the People or to the defendant, provided, however, that to support a verdict of guilt, the evidence, whether of one kind or the other, or a combination of both, must carry the convincing quality required by law, as stated in my instructions.
"One type of evidence is known as direct and the other as circumstantial. The law makes no distinction between the two classes as to the degree of proof required for conviction or as to their effectiveness in defendant's favor, but respects each for such convincing force as it may carry and accepts each as a reasonable method of proof.
"Direct evidence of a person's conduct at any time in question consists of the testimony of every witness who, with any of his own physical senses, perceived such conduct or any part thereof, and which testimony describes or relates what thus was perceived. All other evidence admitted in the trial is circumstantial in relation to such conduct, and, in so far as it shows any act, statement or other conduct, or any circumstance or fact tending to prove, by reasonable inference the innocence or guilt of the defendant, it may be considered by you in arriving at a verdict."
"I instruct you further that you are not permitted, on circumstantial evidence alone, to find the defendant guilty of the crime charged against him unless the proved circumstances not only are consistent with the hypothesis that the defendant is guilty of the crime, but are irreconcilable with any other rational conclusion." (Emphasis added.)
In People v. Bender,
27 Cal.2d 164, 175, 177 [163 P.2d 8] (relied upon by defendant) we said in holding that the trial court should give an instruction of its own motion embodying the principle " 'that, to justify a conviction, the facts or circumstances must not only be entirely consistent with the theory of guilt but must be inconsistent with any other rational conclusion.' " (8 Cal.Jur. 371, § 405.) We also said there that the jury had been told that " 'If the evidence in this case is susceptible of two constructions or interpretations,
[46 Cal.2d 562] each of which appears to you to be reasonable, and one of which points to the guilt of the defendant, and the other to his innocence, it is your duty, under the law, to adopt that interpretation which will admit of the defendant's innocence, and reject that which points to his guilt.' This instruction is eminently proper as far as it goes. To it should have been added a direct statement of the precise principle under discussion." (Emphasis added.) It will be noted that in the case under consideration, the "precise principle" was given to the jury, but the instruction which was given in the Bender case was here omitted. In the Bender case, we held that under the facts there presented, the failure to instruct fully was not ground for reversal.
The evidence here is entirely circumstantial. No murder weapon (or weapons) were ever found; no fingerprints matching those of defendant were found in the ceramics shop. The most incriminating evidence against defendant is that he was identified as the man coming out of the back gate of the ceramics shop. Defendant's theory was that he was not guilty; that he was not in Los Angeles on the 20th, although he admitted having been there on the 3d through the 8th or 9th of September when he left for Texas. From the resume of the evidence heretofore set forth, it appears that at the time the case was submitted to the jury reasonable inferences of either guilt or innocence could have been drawn therefrom. The jury could have disbelieved the identification testimony of Mr. Yonadi who said it was the defendant he saw coming out of the back gate; it could have disbelieved the testimony of Mrs. Simons who said that the defendant was the man she had seen in the areaway because she recognized "the lower part of his face" from a colored picture. Under the circumstances here presented, that part of defendant's instruction bearing upon two reasonable interpretations, or constructions, of the evidence should have been given. Defendant's offered instruction was refused because the trial court felt that it was not good law in that it "virtually says that when the evidence is equally balanced the defendant is entitled to a verdict of acquittal" and because it was in conflict with the reasonable doubt instruction. [16] In a criminal case the prosecution must prove the defendant guilty beyond a reasonable doubt. Therefore, if the evidence is equally balanced, the defendant is entitled to an acquittal. Further, there is in the proposed instruction nothing inconsistent with the instruction on reasonable doubt. The offered
[46 Cal.2d 563] instruction was a correct statement of the applicable law and should have been given.