Which of the following is a method of gathering information on suspects?

The method of gathering information on suspects that is most effective and reliable involves questioning the person about their identity and conduct. This approach allows law enforcement officers to obtain direct information from the individual, helping to ascertain their involvement in any criminal activity. By asking specific, targeted questions, officers can gather relevant details that may lead to further investigation, corroboration of alibis, or discovery of evidence.

This method is proactive and involves engaging the suspect in a conversational manner, ensuring that the information collected is both pertinent and can be cross-referenced with other sources. Such direct questioning can serve multiple purposes, from clarifying the suspect's whereabouts to verifying their involvement in an incident.

In contrast, some of the other options present methodologies that are either unreliable or less effective. For example, interrogating known criminals may yield some insights but relies heavily on the credibility and willingness of those individuals to provide information. Blindly following leads without verification is not a systematic approach to gathering intelligence and can lead investigators astray. Waiting for tips from informants places the onus on external sources, which although valuable, does not actively contribute to building a strong case through verified information gathered directly from the suspect involved.