Which of the following is NOT a way to establish probable cause?

Establishing probable cause typically relies on evidence that is credible, substantial, and verifiable. One of the most significant factors in establishing probable cause is the reliability of the information being considered. Direct investigations or reports provide firsthand observations and facts that are critical for forming a legitimate basis for probable cause. Circumstantial evidence can also contribute effectively, as it builds a context that suggests possible reasons for further investigation.

Conversely, while second-hand statements from reliable sources can offer valuable insights, those derived from unreliable sources lack the necessary credibility and may lead to misinformation. Since second-hand statements from unreliable sources do not provide a sound foundation for establishing probable cause, that option is the correct choice for what is NOT a legitimate method.