Defendant's conviction for first-degree murder is affirmed, but the case is remanded so that the Superior Court may consider a motion for a new trial in the first instance. The amended information charged this defendant under 14 V.I.C. § 11(a) as an aider and abettor to first degree murder. Without a confession, the corpus delicti rule is wholly irrelevant to this case and, instead, the People had a duty to prove beyond a reasonable doubt each element of first degree murder. Where a body has not been found, the People must produce sufficient circumstantial evidence for the finder of fact to infer beyond a reasonable doubt that the alleged victim is, in fact, dead. Then the People must prove that the death was caused by an unlawful killing. In this case, while the testimony of the government's sole eyewitness must be viewed with special scrutiny, it was not inherently improbable or incredible and it sufficiently proved all elements of murder in the first degree. Thus the Superior Court correctly denied a motion for a judgment of acquittal. The Superior Court also correctly denied the defendant's Fifth Amendment due process motion to dismiss based on pre-indictment delay. A mere argument of presumed prejudice due to the passage of time, without more, is insufficient to support a constitutional violation, and here the defendant failed to show that he was actually suffered any substantial prejudice in a way that impeded his defense or affected his right to a fair trial under the Fifth Amendment. The Superior Court may grant a new trial in the interest of justice pursuant to Superior Court Rule 135, and this defendant moved for such relief based upon the absence of physical evidence that he committed any of the alleged crimes and the argument that testimony of the only eyewitness was unbelievable. The Superior Court erred in concluding that it was obligated to deny the motion due to untimeliness because the ten-day deadline in Superior Court Rule 135 is a claims-processing rule and not jurisdictional. It is established solely by court rule and may be extended or waived. Here, the People admit that it did not object to the late filing of the motion for a new trial, and the Superior Court should have proceeded to address the merits of the motion. When deciding a motion for a new trial, the Superior Court is uniquely situated to weigh the credibility of witnesses and it is this special function that necessitates a remand, especially in a case such as this where there is not an abundance of evidence indicating guilt and the credibility of a primary witnesses is, at best, questionable. Therefore this case is remanded to the Superior Court so that it may consider the issue in the first instance.