In legal proceedings, the sufficiency of evidence varies depending on the jurisdiction, the specific circumstances of the case, and the legal standards applied. Generally, having one eyewitness can be sufficient to establish guilt, especially if the testimony is credible, corroborated by other evidence, and consistent. However, the credibility of the witness, the quality of their testimony, and potential biases or inconsistencies are also considered. In many cases, multiple forms of evidence are preferred to establish guilt beyond a reasonable doubt. Ultimately, it's up to the judge or jury to weigh the evidence and reach a verdict based on the applicable legal standards.